Home Forums Club Races Racing Calendar, Classes & Regulations BRM GROUP C DISCUSSION

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    I appreciate your input and agree with your points to a degree.  I too never ran wing cars in the 70’s but did run AFX G-Plus cars in the 80’s and they did run foam in their stock configuration.  Having said that, I am not married to foam but the big cars work so much better using them, or at least they did at one time.  We need to figure out what we need to do to get the tires to get some grip.  I will be at the track next Saturday working the problem.  Any and all help would be welcome.

    RevoSlot – the tires for RevoSlot were hard to come by and were very inconsistent.  The idea was to move to a foam tire that would be far more consistent, easy to source and equally if not more drive-able.  The other thing is the Scaleauto foam tire is the same width for everyone where the RevoSlot Porsche uses an 8mm rear tire compared to the Marcos 9mm and the Viper/Toyota 10mm.  Now all the cars will run the same 10mm width foam tires.

    Realistic Speeds – I don’t think the BRM Group C cars speed will be out of scale, in fact, I believe it will be closer to scale than the other series we run.

    The Wear Lines on the Track – The wear lines on the track can be removed after we run the series or we can stick with foam tires moving forward.  A question the club will have to answer.


    — The posted BRM GP-C rules seem to be missing the update regarding the Scaleauto ProComp SC2424p rear wheel tire assemblies. The BRM S-021SS are still spec’ed.
    — Sponge/foam tires typically work best with some corresponding product on the track. Remember that when we ran at Dallas the track had a very light glue on it (it was not ‘tire cleaner’) that they also used for sprint races and other 1/24 classes.
    — Have the 22-Shore BRM tires (S-020S) been tested? …just asking…
    — MOTORS – so Pink has lowest RPM but most TQ (340gm); has anyone tested the Red motor with 212gm TQ – perhaps there would be less fishtails with the lower torque?
    — RANDY – it’s ‘rear tires … not less than 27.5mm …’ (1) this happens to be the stock diameter of the SC2424p so the implication is that only basic truing is allowed/or needed (2) a smaller O.D. either by wearing or truing would be a slight advantage from getting the CG lower.

    ?? TIRE QUESTION – What does this statement mean ‘You are not allowed to true any tires with an angled profile’? I don’t think we have a razor style truer that would make tapered cone shapes possible.
    Is this just another Cling-on from the specs inherited from Alan’s series (inherited from Euro rules)?

    ... she's got real fat tyres and everything !!! ... Deep Purple Hiway Star


    Answers to the points brought up above are listed below.

    The rules have been updated to show the new rear wheel/tire spec – Scaleauto SC-2424P.

    The hard BRM foam tires put down a layer of harder rubber on the track that is difficult for the softer Scaleauto tires to hook up on.  We will be cleaning the track to pull up the hard rubber and put down the softer Scaleauto foam rubber.

    I have tried shore 30, shore 22 and shore 15 BRM rubber tires and none of them worked well.

    Motors – I personally would not a red motor but I have not actually run one recently.  We did run them in some of our previous BRM series.  Maybe it could work.  I’m not going to try it but its left in the rules in case someone would like to give it a try.

    Rear tire specs have been updated.  The minimum rear tire diameter at the start of a race is 26.5mm.

    Tire Question – This is not some Euro carry over rule.  This rule exists in many of the series run in the States.  Our truer is not set up for putting a conical shape to the tires but it can easily be done.  The purpose is to have a smaller contact patch for front tires so their is less drag when running the large width wheels/tires.




    Thanks for the clarifications Marty! I assume after cleaning the track and the discussions regarding rubber tires the rules may be changing again regarding using ‘rubber’ Shore-30s and perhaps different Max/Min ODs?
    BTW – after you left I put on some BRM rubber tires with Pink motor and got some reasonable traction as I added some rubber to the track.

    ... she's got real fat tyres and everything !!! ... Deep Purple Hiway Star


    BRM rear Wheels S016. S017
    S-020 – Rear Tires for Group-C – Standard (30 Shore)
    S-022S – Front Tires for Group-C – Lowered
    S-019 – Wheel Inserts – BBS 5 Spokes plus Porsche BBS TurboFan covers.

    ... she's got real fat tyres and everything !!! ... Deep Purple Hiway Star

    Radial TARadial TA

    Can all of the tire truing machines be set up for the 1/24 wheels?  I used one a few weeks ago that had been set for single tire truing.  I don’t want to waste time trying to figure this out for each machine if not possible.

    Are shore 30 rubber tires mandatory, or can we use shore 22 if available and the weather changes drastically?

    There is no maximum weight listed, so is that free choice?


    The axle diameter on the 1/24 scale cars is 3mm – just like the RevoSlot’s.  I don’t know which of our truer’s other than the Hudy will work with a 3mm axle.  If you can’t find the 3mm axle for the Hudy you can use your BRM axle as the truer axle.

    I would not suggest shore 22 tires.  Think of the added weight of these cars and the acceleration these cars have coming out of the turns.  We run shore 30’s because we have tried 22’s and 15’s in the past only to discover they shred rubber like crazy.  You will be surprised at how much rubber comes off of the 30’s much less the 22’s.  Having said that, you are more than welcome to try them out.  We will allow 22’s and 15’s for those brave enough to run them.

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