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Old 02-10-2013, 04:44 AM   #1
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Default Hex 12mm Conversion - Mardave?

Hi All

Has anyone come across a 12mm Hex wheel conversion for a Mardave V12?

I've carried out some pre-lim mods to get more traditional and 1/10th wheels on my Mardave, but a really simple solution would be a 12mm hex adaptor of some kind.

I've googled and eBay'ed but can't find anything...

Cheers
Lea
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Old 02-10-2013, 06:20 AM   #2
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I would have to ask why you want to do this. If you are just trying to fit rubber tyres on the car then tyres designed for Tamiya Minis such as these from Shimizu will fit on the Mardave wheels. If you are thinking of running touring car size wheels you will have problems with getting the gear ratio low enough to prevent the motor overheating.

Rears you could probably do by getting a pair of clamp type hex drives and using them to hold the gear mount and left side spacer on the axle. The fronts are a whole bigger problem, unless you want the hex drive to spin loose on the axle with no bearings, you will either have to drill out the hex drive to fit bearings or replace the axle and steering assembly with something with a rotating axle, such the Tamiya F103GT front steering blocks.
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Old 02-10-2013, 09:10 AM   #3
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Hi Terry

Spot on Terry, I'm looking for rubber in principle, but having the extra ground clearance is a boon for jumping down kerbs. Thanks for the link to the Tamiya's especially as I keep been told there is no rubber for Mardave's anymore :-(

I've also just fitted a Mardave diff and it's a disaster :-( It keeps turning the nearest the diff nut's off and the diff performance is effected by the wheel nut tightness. I've finally realised why, the rear shaft can turn in the opposite direction to the wheel, as the wheel is driven directly from the diff output AND there are no bearings to compensate.

Trying not to be critical, but even with original wheels this will be a problem for everyone 'upgrading to a Mardave diff'...bad decision on my behalf I think :-(

And yes, I'm suffering from major motor temperature problems! But what's the primary cause - clearly the wheel diameter has increased (although the car seems about the same speed overall), is it motor load caused by increased torque requirements of acceleration?

Cheers for any help - you can tell I'm a nuub, but having plenty of fun!
Lea
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Old 02-10-2013, 10:06 AM   #4
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Most GT12 racers prefer the Schumacher Supastox diff, the end of the diff side axle does not rotate inside the wheel so the wheel can be tightened down properly. The Mardave diff works but you have to maintain and adjust it regularly.

Technically there isn't any rubber tyres for Mardaves, and there never have been. But Mini wheels just happen to be the same diameter and width, although with ribs to locate the tyre. Make sure the rubber tyre is lined up properly on the wheel before gluing and you should have no problem getting them on straight.

Your motor will be getting hot because the overall gear ratio (how far the car travels for one revolution of the motor) will be increased greatly by changing to bigger tyres. You can compensate for this by fitting a smaller pinion gear and a bigger plastic spur gear but with touring car size tyres you will find it hard to get spur gears big enough to compensate, then you will probably not be able to get the motor far enough forwards to clear the bigger spur gear.

If there is a lot of extra load on the motor the car won't go any faster because the motor can't overcome the extra load to get up to speed.

You will get a lot more enjoyment out of your Mardave if there is a club near you where they race them, they are pretty popular cars. There is a list of clubs on Centralbooking to see if you can find one local to you.
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Old 02-11-2013, 12:39 AM   #5
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Hi Dave

We're not into clubs yet to be honest as the fun is in the modifications currently, but maybe in the future, probably visit as a spectator to get the atmosphere and our local model shop often offer a local place to come along and see!

Interesting you mentioned the Schumacher diff, our local shop also highly recommended this but as it's twice the cost I didn't take it (we are on budgets as in need of a second charger also) - and perhaps I wasn't listening when the benefits were explained :-( Hey ho, you live and learn!

The Schumacher diff quote says it all '....simple tightness adjustment without the need to disturb the tension when removing the wheel.' this is exactly what differentiates it from the Mardave Diff and would resolve the issues I've discovered the hard way. Trouble is it's just too much of an outlay, so it's back to the standard locked diff for now, and I'll look at incorporating my own bearing in the wheel ;-)

Thanks for your pointers and advice, much appreciated.

Lea
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Old 02-14-2013, 08:44 AM   #6
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Uhm, haven't seen these before - cheers Terry:

hpieurope_com/piw.php?lang=en&partNo=72044

I'm wondering what the minimum axel width is - 4.8mm?
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Old 02-14-2013, 10:11 AM   #7
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The 4.8mm is the thickness of the hex, 4.8mm keeps the width as narrow as possible, the 6mm hex drives listed in the 'related parts' are 1.2mm thicker to move the wheels out 1.2mm each side to widen the car. They are designed to fit a 5mm diameter axle.
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Old 02-14-2013, 12:58 PM   #8
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Cheers. The axle on the Mardave is 4.5mm (measured), what you reckon, tighten the hex screw a bit more?
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Old 02-17-2013, 02:12 AM   #9
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Fitted a simple bearing in the wheel, now can tighten wheel nicely without affecting the diff tension, hoping this will prevent the nut spinning off. :-)
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Old 02-18-2013, 04:00 AM   #10
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Quote:
Originally Posted by terry.sc View Post
Mini wheels just happen to be the same diameter and width, although with ribs to locate the tyre.
Will Tamiya mini tires fit all wheels for 1/12 Mardave:

http://www.mardave.co.uk/all-parts/t...ls/wheels.html

Cheers :-)
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