Trueing Tyres?

[gkilner]

Hello All,

I've just been buying a Mardave V12 to race at my local club, I've been reading a lot about making the foam tyres true. Can someone explain this, is special equipment needed? or is it just a case of using a craft knife to trim them?

Am really looking forward to racing, I used to race a Mardave Meteor Buggy about 17 years ago!

Many Thanks,

Gavin.

[Pug205gti]

I used to just clamp a drill onto a bench, put a bolt through the wheel you want trued. and use a sanding block to get it as true as possible.

Nice and easy for soft tyres but with harder tyres like Jap meds the rubber melts so It is a lot harder to take the tyre down in size.

Nowadays I use a Hudy Tyre Truer, so much easier :)

[Simmo]

Alternatively, you can use an old mardave V12 back end to get the wheels and tyres square.. with the rear pod section clamped in a vice, staple some sandpaper to a block of wood (so you know its flat) and try to get the tyres running flat and true. I dont think you will be able to do JAPs in this way, I did try (before i bought my own truer - which has seen lots of action!) but it just over heated the tyre..

Trueing means shaping the tyre so it runs true to the ground, i.e parrallel. Believe me I can make quite a noticeable difference running untrued tyres.

[TheChard]

I have looked at various tyre truing devices being sold by manufacturers and in basic terms they work on the same principle as a small lathe.
If you feel the need to trim or true your tyres to within 0.5 of a millimeter then they are for sure the way to go so you should be able to spend around £150 give or take.
The other option is as mentioned by using a drill clamped in a vice, works but not the best option as some of the tyres when trued can grab the sanding pad or sheet your are holding with quite a force.
I have managed to true and trim my wheels using a cheap pillar drill purchased from a large DIY chain for less than £50 no good for carting to the track but excellent for doing your tyres at home ready for the meeting.

I cut a V12 rear axle in half and slid onto that a used spur gear, this then is placed in the drill chuck allowing the wheel to be bolted onto the axle.

I have placed a vertical slab of engineering sandpaper glued on a block and then clamped that to the drill table that can be lifted up and down and in and out using the drill adjustment clamp at the back.

Put the wheel and tyre onto the axle set the table to the required height and diameter switch on the drill and slowly pull down on the drill handle a couple of times and there you go nice flat smooth foams.

If the tyres wobble slightly on the edges this can be trimmed while still running in the pillar drill by Carefully and slowly pushing a craft knife blade into the foam making sure it doesn't snag.

It is also VERY important to remember to slightly radius the inner and outer edges of the tyre to prevent the car flipping over in tight corners.
Spend the money you have saved on buying a tyre truer on some more Mardave wheels and tyres.
ps:I also use Mardave double sided tape to glue my tyres neat,easy and strong and when the foams are beyond use just peel of the foam and soak the wheel rim in white spirit or meths and you have a perfectly clean rim to start again. :D

[gkilner]

Thank you for the replies I understand this much better now - I don't think I'm ready to shell out £150 yet, I'll see how the racing goes. The pillar drill sounds a good idea.