lazer zxr for winter racer
 

Hi all. First of all i would like to thank you for the advice and help you gave me in a previous thread for my zx , but this car has now become spares for a lazer zxr . I have stripped cleaned and rebuilt the zxr to the manual. I am planning to use the car over winter at two venues but want to keep the car as original as possible or with period upgrades.
The items i have changed are the shock towers for carbon fibre items with the front having the much needed bridge for strength, associated plastic servo mounts. Also the pistons in the option house shocks for modern lazer mk5 items (w5181-03 piston set). I am using lipo saddles 5600mah 95c and brushless 6.5t hpi motor 100t spur with 23t pinion.

Before i put my pride and joy up against the new cars i thought i would ask for the knowledge from the expert vintage lazer racers.....

is the manual a good starting point for a set up of the car?
What shock oil/pistons and lb springs to use front and rear?
Will the slipper be up to the job with a 6.5t brushless?
Any weak areas for the car to watch for?

The track surfaces i will be racing on are a hard rubber floor(indoor running track) , also a mixture of carpet/polished floor.

Keeps us up to date how you get on just getting my lazer zx ready for the winter after its last race with me in 91, I changed my spurs for the Teflon back in the day so staying with them.

I think your going to snap the belt. Also you should be posting this on the main Lazer thread. Im designing a belt tensioner block to be attached to the gearbox but youll need to cut a section away to do it. Also slipper may not be up to the job either but with a tensioner fitted you can tighten the slipper. Tyres yellow mini pin work fine, gear ratio well id opt to start with a 23 and go up or down considering. Id go for less accelaration more top end to save the belt but would rather you used an 8.5 with the standard gearbox

Set up, well i used traxxas shocks but if you use kyosho shock seals and use three holes front 2 rear you could try 50 front 30 rear with schumacher grey front and schumacher white rear. May also try size 2 all round 35 frt 30 rear.

Had time to give my zxr a test at my local track yesterday. I Was very impressed with it but it did seem soft on the front end lifting inside front wheel in the corners. I will try thicker oil in front . I was happy testing and tweeking, camber etc.......then it happened! Rear belt broke!.....well thats what a thought, got home stripped gear box to find all the teeth had come off!

Get a new LA11 and a new rear belt. Then before you rebuild it hold fire for a short time as I am almost done with my redesign as I have had a few carbon fibre brackets sent across to me and will try building this weekend and if happy will order some bits and pieces and sell as a small added kit with manual on how to fit the rear belt tensioner.

Also are you sure its not the rear you need to thicken. What surface are you running on and what oil and springs and pistons are you using? Also what tyres and inserts and are you using a roll bar?

Your belt tensioner sounds a good idea as my guess is the belt on the none drive side slaps about at speed and causes the belt to jump resulting in a broken or stripped belt.

i understand what you mean with the rear end, but on the track the rear seemed rigid with not much roll and in the corners it skipped/bounced a little, in the slow corners the car wanted to hook.
ive been testing my car on high grip astro but want to mainly use it indoors at two venues with a hard rubber floor ( indoor running track ) and also carpet/polished gym floor.

ive been testing the car on astro using scumacher yellow mini spikes with medium inserts outside row cut off front and rear. Also i have medium and soft foams and soft rubber slicks which i was thinking of trying indoor.

my set up so far is as follows....

FRONT
Option house shocks with zx5 fs piston 2-c, 35wt ae oil and original gold springs (maybe silver but i think gold as they look faded)
lower shock position is outside hole
upper shock position is 70mm apart (lots of holes to choose)
camber link on tower is top row 3rd hole in from outside.
been thinking about trying ae blue springs??

REAR
option house shocks with zx5 fs piston 2-b, 30wt ae oil and kit black springs.
lower shock position is middle hole
upper shock position is 75mm apart (again lots of holes to choose)
camber link on tower is top row outside hole
camber link on hub is middle hole top row.
rear brace is number 1 and position is as manual
been thinking about trying ae silver springs??

i do have the original black pistons with two holes and the red pistons with one square notch on the edge if they will be better to use?
I would like a roll bar but don't know were i could find one or if any can be made to fit from a current rc car...was thinking b44 or another one i seen which has little clips for mounting it.

Pricey but a complete set is available on ebay. See link below.
http://www.benl.ebay.be/itm/Kyosho-L...5#ht_330wt_932

Brgds,

Too expensive. do a search on the part number on google and ebay and youll probably find it for maximum 30 euros.

Your belt tensioner sounds a good idea as my guess is the belt on the none drive side slaps about at speed and causes the belt to jump resulting in a broken or stripped belt.

Belt doesnt jump, it fluctuates under power as there is nothing keeping the belt from moving in the gearbox other than the pulleys and those crap brass bushings which actually dont do anything. These were taken out by myself and also Jon Tucker (he qualified for the worlds with a ZXR) as they damaged the belts. The belt needs a bit of tension to stop the fluctuation as that can stretch the belt and bang it snaps whereas with a tensioner it keeps it all in place and less fluctuating means it stays pretty much perfect and lengthens the lifetime of the belt by several years, quite possibly youll get five years out of a belt if maintained correctly. Im lasting a bit longer than that on mine.

i understand what you mean with the rear end, but on the track the rear seemed rigid with not much roll and in the corners it skipped/bounced a little, in the slow corners the car wanted to hook.
ive been testing my car on high grip astro but want to mainly use it indoors at two venues with a hard rubber floor ( indoor running track ) and also carpet/polished gym floor.

I believe the back is too hard, first would go down a spring. Also would advise using a longer tie rod adjustment on the rear but not the longest setting and that way gives you more droop and also does make a difference on this car. A roll bar on high grip is needed as I only ever use it indoors. I would also set the car a bit lower so Ujs should not be level and be slightly under when on the track on the rear and also use a larger wing. Springs personally always go softer on the rear so me I would opt for trying associated silver but may go down to green on the rear with 30 weight and on piston size smaller than the front.

Front I use the top outer tie rod hole and use the blue steering with a zx steering plate as then you have zero bump steer. I know Jamie Booth preferred the ZXR angled steering plate but I couldn’t get on with it so down to you. Springs on the front start with associated blue but may go down to silver, personally I found Losi red works well on mine better than the blue or silver but my shocks are traxxas. Piston needs to be one softer than the rear which does sound weird but try it and see.

Front outer hole used on the front castor block and longer Ujs makes a huge difference so hope your using that.

ive been testing the car on astro using scumacher yellow mini spikes with medium inserts outside row cut off front and rear. Also i have medium and soft foams and soft rubber slicks which i was thinking of trying indoor.

Answer Blue inserts are what I use and on carpet and shiny floors I use mini pins but on astro yes mini spikes are fine. TBH inserts are really down to preference so go with what you feel suits you.

my set up so far is as follows....

FRONT
Option house shocks with zx5 fs piston 2-c, 35wt ae oil and original gold springs (maybe silver but i think gold as they look faded)
lower shock position is outside hole
upper shock position is 70mm apart (lots of holes to choose)
camber link on tower is top row 3rd hole in from outside.
been thinking about trying ae blue springs??

REAR
option house shocks with zx5 fs piston 2-b, 30wt ae oil and kit black springs.
lower shock position is middle hole Try outer as well
upper shock position is 75mm apart (again lots of holes to choose)
camber link on tower is top row outside hole
camber link on hub is middle hole top row.
rear brace is number 1 and position is as manual
been thinking about trying ae silver springs??

i do have the original black pistons with two holes and the red pistons with one square notch on the edge if they will be better to use?
I would like a roll bar but don't know were i could find one or if any can be made to fit from a current rc car...was thinking b44 or another one i seen which has little clips for mounting it No harm in trying, the softest one is the best to go with for this car

I will try to post some pics of my ZX on your thread this weekend so you can see my tie rod placement. Yes my car is set for carpet but youll get an idea from it. Also are you using any weight on the chassis as don’t forget the car was designed to carry roughly 220 grams more weight, so as your now using Lipos and this does change the characteristic of the cars handling. Mine ive addded 85 grams on either side but have the option of adding brass plates doen the middle between the lipos. Im testing my new chassis with these weights in two weeks time and will uipdate on it how it went with all the weight added and also without.

Where are you based again as I have forgotten.

Thankyou for the advice welshy40, i will try what you have advised me on and see how it goes.

uj's
i am using the original front uj's and the original dog bones in rear....what would you recommend to use?

weight
Regarding the weight of the car with using lipo's, when i made my lipo holders at work i designed them so they would bring the lipo's up to the same weight as some old ni-cads i had in my loft (380g). I forgot to mention that i am using zx gear diffs front and rear, would i be better off putting the zxr ball diffs back in?

i do have a lazer zx aswell .....would the zx be more competitive indoors then the zxr?

i'm based in north manchester

thanks for the link but to expensive at £40

Ujs well i did do a post aling with Iso in the Lazer thread so you should find something within the last 20 pages.

Zxr would be a better option for you. Gear diffs are fine but would recommend packing out with grease and not oil.

Pics of your lipo holder please.

Ive just completed my build of my tensioner for the rear gearbox and needs a slight mod and then i can order a few bits and pieces and will sell as a tensioner kit. You need about twenty minutes but better doing it at a relaxed pace so you dont mess it up so maybe an hour to do it.

Pics will follow on the lazer thread sometime this weekend

Forgot to mention but as your in Manchester doing the Maritime race event in kent is a bit far for you to come to learn about the car.

Hope these pictures help. If not just ask. FYI Lipo tray not yet fitted as the design was flawed.

pics of my lipo holder as asked, simple really couple of end plates and a plate down the middle attached with double sided tape to stop lipo's moving around,i am going to make the plate in middle in different weights if i feel the need add or remove weight

impressed with your car welshy40, ive noticed the odd modification on it from the standard zx.....is that your re-release tub chassis i see? Also is the front gearbox casing an alloy item you have made?. I have been thinking of making my own version at work when the time comes.but for now i still have four bnip.

Here are some more pics of my car, ive followed your advice but yet to test the car as i need either a slower motor or a belt tensioner, as you can see it is pretty much original apart from the shock towers.

The Front caster blocks in last picture, can anybody tell me what make they are please?

They were made by Teamline, kinda like a factory team optional upgrade. They are much more robust than the original items and came in two different castor options. They were also ballraced round the kingpin and the ones in the photo appear to be missing the flanged bearings.

Looks nice and only things id do is turn the very rear pivot block upside down as it gives more kick up and makes the rear slightly better, also make the angle on the front shocks on the tower the same as the rear. Your lipo design looks very similar to my original design in cf ive been using for the last couple of years, since the trf511 came out. Ive designed my middle block with a milled bottom so left and right have flat spots higher up so i can fit brass weights in the cell holes and a brass plate ontop plus brass weights on the centre block as well as having the option on half weights as well. This item bolts to my chassis. Updated design on my tub.

Motor wise when a tensioner is fitted you can easily use a 6.5 motor, me im using a 4.5 for testing and so far havent stripped a belt.

Odd mod is an understatement. About 20 percent is original, new designs are total new rear gearbox design including new layshaft and vts slipper clutch, new rebuildable ujs, new rear hub from the zxs, pure ten steering, new front & rear towers, Top deck & new updated tub now available and one off front gearbox. Side walls on that are cf with a top and bottom section that screws onto the cf wall so you can mount the top deck and bolt to the chassis, and a 3mm higher rear top deck mount which ive persuaded a 3d maker to sell as well, but mine is a one off alloy & testing the 3d plastic soon when it arrives. Main bit of the gearbox is thin alloy.

Chassis is a spin off from my very first design with a few tweaks. You can buy but youll need to specify what design you want cut from the tub but would advise sticking to the side walls height being 20mm high and the back end wall edges being rounded off. Every one has their own idea but hey i only designed the original tub so have a valid reason.

Belt tensioner is designed and now am working on a manual and finding the correct parts to sell as a complete package so all you need do is cut the gearbox to my specifications and game on.

i have the bearings still so will give them a try. Thanks for the info.

Well im going to give my car its first outing at a meeting sunday, hope all goes well and my rear belt holds up, ive just added a bit of a tensioner mod but its not the best but fingers crossed it will work for the day.....welshy , how far off are you from completing your tensioner? Sounds like you have almost finished from reading the lazer thread.

Just bought the screws, bearings, nyloc nuts, now need the cf plates, washers and spacers and its for sale. Reckon two weeks and game on. Your designs ok but your limited as that bearing stops you using pinions and movement of motor. That believe it or not was my first tensioner design so nice attempt.

Well my lazer was put up against todays best 4wd cars and i was impressed, it kept the pace and i was taking it easy. I was also impressed with the one way system when i got the hang of it, even the original ball studs held fine . My quick diy tensioner did the trick as the rear belt held up but the bearings i used did get very hot! Really looking forward to my next race meeting.

Set up wise it seemed very good (thanks for advice welshey) but may give the ball diffs a try and maybe a zx top deck with belt cover to stiffen it up and see how it goes.

Well you could buy the cf tub as that stiffens it big time. I dont think the zx top deck will stiffen it, i think it give flex. Yes bearing gets hot and blocks motor movement but soon my design will be available. Youll find once its dialed youll be easily as quick if not quicker than the new cars

As James says, the ZX two piece top deck isn't a good idea. It does keep the chassis as stiff as the ZX-R setup, but only if it is run with the chassis spine that lock the gearboxes together. You are just adding more weight and making it harder to work on just for the sake of keeping dust out of the front belt.

As for snapping rear belts, I've never had that problem after running every week for 6-7 years on carpet. I snapped a few early on, when I tried drilling through the ZX centre diff and bolting it together, until I took the balls out and ran it as a slipper. Kept the roller guides on the layshaft as they do stop the belt skipping which damages the pulleys, leading to belt wear. Never had a problem with it running 10-12 turn brushed in it back then, just allow the slipper some movement. It can be tricky finding the sweet spot for the slipper to give under shock loads while still giving full drive, but you just have to adjust the nut by fractions of a turn until you get it right. Had it out again recently running with a 10.5T in it for racing and general bashing...
http://www.tamiyaclub.com/tc_userima...2719_5_350.jpg
:eh?:
and still not damaged a belt. I don't think you need to worry too much about it. After all the belts are exactly the same as those in every other modern belt drive buggy.

Terry, the tensioner ive designed is based on my proto cf gearbox and is there if you feel the need to go for more power such as a 5.5 orr 6.5 and should handle it with no complication.

Im like you with a 10D i very rarely snapped a belt but brushless has so much torque the belts need a little tensioning to handle the power.

Also have you modded a car for touring car racing and if so what did you do with the shock towers?

My touring car chassis didn't have much that wasn't changed some way. Home made shock towers to run short front shocks all round and wider at the front to move the shocks further out on the Mid wishbones used. Bigger gearbox brace over motor. Home made top deck, it started life as a ZX. Optima wishbones and uprights. Gear diffs filled with Kilopoise grease, they moved easily when cornering but when one wheel slipped the grease would stiffen up to lock the diff. No minimum weight limit, so everything was cut off that could be removed. Pictures are rubbish as they were taken years ago.

http://www.tamiyaclub.com/tc_userima...00324415_2.jpg
http://www.tamiyaclub.com/tc_userima...00324415_3.jpg

Cheers Terry, ive built my chassis minus wishbones, shock towers and hubs. I see you kept the angle of the front shocks and less on the rear. Interesting so will be basing my design around yours. Wishbones im having a new set made.

Rear shock are mounted on the front of the arms purely because I'm using Optima arms, rather than choosing to mount them in front.

Using the Optima arms the shocks are mounted right out near the outer pivot, I would say around 10mm near the end of the arms so there is very little leverage and I could use standard Kyosho gold springs.

That's interesting, wonder how would that work on a modern gear diff car.

I packed mine with vaseline (no jokes please :thumbsup:) in the 90's and worked great on high grip as well as medium grip. Won quite a few events with that.

Kilopoise grease is used for sliders and hand controls on machinery, where they need to be able to move easily at slow speeds but to add a damping action at faster speeds. It would be interesting to try, but it costs £80-90 for a small tub of it. I was lucky enough to know someone at the time who borrowed it from his work.

rear belt
 

Im running a 6.5t brushless in mine which may of been the problem when i stripped the teeth off the rear belt, i could hear the belt jumping under acceleration. Adding the bearings as in picture above worked but now have no way of adjusting the tension if i need to. I am now on with trying another idea that will supply adjustable tension to both front and rear belts.

As for my top deck,i will stay with the zxr one, the gear zx diffs i will keep on using for less maintenance over the zxr ball diffs but try some grease or vaseline.

Rob, wait a week or two, thats all and you can buy my tensioner. One tensioner only and ive based it on my cf gearbox design that i have been using and developing over the years. Its got plenty of adjustment sections so when the belt slackens you can adjust and tighten so giving more life to the belt. Its also not portruding so means you have no worries with gearing up as the motor wont be blocked.

Copied from page 214 where youll see pictures as unfortunately i couldnt copy. Pics show my proto cf plate with bits and pieces but have now refined it and just done a manual as well. Hope it help you make your mind up.

As promised here is my first tensioner design for the standard gearbox. Im going to get a plate made from fibrelyte and that should make life a bit easier but may need to cut a fraction more away from the gearbox for it to work correctly. Still its a start and feels set correctly.

Also ive moved it from my preferred position which I use on my prototype CF gearbox as of I used a similar position you cant use the full range of pinions as the tensioner gets in the way. This was it avoids the motor and tensions the belt correctly.

As always opinions are always welcome.
Attached Thumbnails

My idea for my tensioner has changed. first pic was my original idea, but now just a front tensioner. The rear was going to be like the front but running on the tension side with the idea that i could get more teeth to do the driving on the la11 pulley by having the belt wrapped around the pulley more but have decided it will create to much stress on the belt and pulley.
Pics of my idea and front pulley.

Ive already designed it all including the front tensioner so would recomend looking at my car pics on the zxr thread. Ive developed over years of testing so would save you time and money in developing by buying mine

It only took me 15mins to make and doesn't cost me anything as i make it all at work using the cnc and manual millers/lathes etc and off cuts.
Do you have any idea of a price for your rear tensioner ?

I didnt know you had that kindof talent, superb.

Yes if you study my chassis in the last couple of pages on the lazer zxr thread youll see my L brace tensioner for the mk1 chassi. Also the rear gearbox tensioner, ive taken my design from my zx cf gearbox and made it fit in the only place on the gearbox where it makes the tensioner work correctly. I cant explain properly as im in a hotel at the mo cleaning my car after a days racing but ive tried every concievable design and found the best suitable for this. I will post some pics next week to show you properly.

Rob as promised this is my proto but ones Im selling will look pretty much the same all depending on the colour of the washers. Its pretty simple but believe me ive tested every concievable method and this is the best, plus it doesnt stop motor movement so stock and modified gear ratios wont be affected.:thumbsup: and also you can tighten the belt or losen meaning your not set to one particular tension setting especially when the belt stretches it comes in handy.