What size wheel bolts do I need for my Ronal R8T's? I know they are a tapered seat. I know the threads are M12x1.5. But will the thread length be the same as the radius seated OEM bolts or do I need longer? Any help or guidance always appreciated.
Sorry Graham I have no definitive answer on this one! All of my R8s have spherical seats. When I wrote to Ronal regarding R8 production, they informed me that the R8Ts were aftermarket with deep dish polished rims. Dependent on offset, the wheel hub thickness will vary. So. Are you fitting to a VW Golf Hub, or similar? If so these are only 10mm thick, so the bolt only needs to stick out 15mm or so, an extra 5mm is sufficient, beyond inside mounting face of the wheel. If using other hubs, or spacers, make due allowances. Now. When I was fitting OZ wheels to my daughter Ruth's 1992 Mk2 GTI these had taper seats. The OZ bolts were naff so I used ASTRA van bolts! These were the correct length, but more importantly were very high grade, 10.9 or 14.9, I can't remember which, so stronger. Take a look in the scrap yards and see if you can find a suitable bolt. Buy new if you wish. Regards, Dave.
Thanks for the info Dave. and thanks to Jonny for poking Dave. My wheels are 7x15, 4x100 and ET28. The wheels will be fitted to VW Golf hubs (10mm depth based on Dave's info), I have also measured the depth of the wheel (not including the tapered seat part) which is also 10mm, making 20mm. Based on the above, am I right in thinking that a 23mm thread length would suffice, just like OEM? Also, if I'm looking at Astra Van bolts, what year do I need to focus on when I'm at the scrappy?
Well Graham we need to do a bit of calculating! Ruth is 40 this year, and she had Mk1s for a few years, so she was 20, or 21, when we built the GTI. If I calculate correctly the ASTRA vans were pre 1997! Dave.
Yeah was certainly no poking from me Another source of tapered seat 17mm head wheel bolts is BMW, they're slightly longer than VW bolts IIRC but I cant recall off hand so double check they're correct for you. Will try to remember to dig one of mine out to measure for you I've had them off many different models in the past, always seem to be fine main thing is finding a full matching set in scrappy as if the bolt heads dont all match it sets off my OCD
UUUUGGGGHHHH BMW!!!!!! By the way Graham. Make sure to use some anti-seize product such as Molyslip 'Alumslip' or 'Nickelslip' on the tapers. Taper seats are very prone to seize that's why high quality manufacturers use spherical seats! The Molslip products are about 11 and 16 respectively, for a 500gm tin. I always use Alumslip on aluminiumised steel exhausts and Nickelslip on stainless steel! John. Is the torque figure for BMW taper seats the same as spherical seats? IIRC VAG is 120Nm for M12!
Graham. I am sure you have realised that I forgot to allow for the thickness of the brake disc! Sorry! So. 4mm extra for the disc. Dave.