Hi should a 1970 royal star have a rear rim lock fitted. I have been offered a rebuilt wheel and tyre and it doesn't have one fitted. What is correct? And what are safety implications? Thanks
Rim locks are only needed if you are going to run the tyre at low pressure off-road to help with generating more traction on soft ground. Without the rim lock, the tyre could rotate on the rim during braking or acceleration and destroy the inner tube. There is no need to use rim locks on a road bike. One of the problems with fitting them to a road bike is that it is very difficult to balance the tyres afterwards potentially resulting in a lot of vibration.
Hi,
The 1970 parts book lists a 'security bolt' 37-3468 for all models so if being very particular for a 'by the book' restoration for concourse competition then one should be fitted. As Spaceman says, it is not necessary for road use and as well as the balance issue they are a pain to fit.
I suspect that they were fitted to all models and even B25s, as the wheels were a common part so easier for production/assembly.
Dave.
I hadn't noticed that before - in fact, BSA appear to list them from about 1966 but, in all cases, only for the back wheel and not for the front. Interestingly, the earlier parts books list 2 x security bolts for the back wheel and the reason for this will be to counter-balance their weight by fitting them on opposite sides of the wheel.
I'm normally a perfectionist in restoring BSA bikes but I would draw the line at fitting rim locks. One of the bikes I ride for green laning has a single rim lock fitting to each wheel which is bad enough when changing tyres but to fit two would make tyre changing a total nightmare. Even for this bike, they are completely unnecessary because I never ride the bike with low tyre pressures.
Hi,
I know that one could be beneficial when a sidecar is fitted as the loading on the tyre is quite different and slipping is more likely.
I know of one combo rider who had to fit one at the German Inter. in 2004 as the tyre, even though correctly inflated, kept moving and pulling the valve out of the tube. I suspect that the pattern rim may been at fault.
Having said that, I ran a fully loaded A10 combo for many years with no such problem but I still had the original rims fitted.
Dave.
Many years ago I restored a 1963 Super Rocket. I did NOTt use rimlocks. I was cruising around 60 on a highway and twisted the throttle all the way open. BAM!!!. The tire spun on the rim ripping the inner tube valve out, and I thought that was the end of me and my freshly restored BSA. I now have 3 restored bikes, and they all have rimlocks!! A couple of wheels I had to drill for the rimlock. They are only needed on DRIVEN wheels i.e. the back wheel.
Greg Wakeman, Virginia, USA
I balance my wheels myself. I will admit you will need more weights but it can still be balanced
I ran a Vincent Rapide and Wessex outfit without a rim lock and never ripped a valve out through a tyre turning.