I am a recent noob to the centrelock world and have been (over)researching the CL tool options. I want something that is compact to pack along to track days and road trips. I had originally just thought to get the big 48” torque wrench (PI version as it it comes with a breaker bar and breaks down into a smaller carry box than most), then read up on the even more compact Renntorq tool. But at the end of the day, can someone tell me why a general purpose $400 planetary gear torque multiplier isn't the clear choice? We generally all already own a 1/2” drive torque wrench and a 1/2” drive ratchet or breaker bar, so add a pipe extension to the reaction bar and piece of wood on the floor and you are all set to remove and install wheels in the air, with less drama, backache and help needed vs a big torque wrench, and save $1500+ vs a Renntorq. The math (multiplier; losses) ain’t even high school. What am I missing?

 

The special torque wrench and a 3/4" breaker bar, along with an extra wheel nut socket are a simple kit to put together for dealing with center locks. A bit of a hassle to travel with though.

I wouldn't want to use a 1/2" drive with the torque involved. Having the assembly drop and damage the wheel would be unpleasant. And wouldn't the reaction arm need to brace against the wheel and not the ground?

 

Most of these torque multipliers are in the 3:1 to 6:1 range, which means the input torque needed for ~450 ft-lbs output falls well within most 1/2” drive torque wrenches’ capability. And, no the ground works just well as a brace as the wheel, and eliminates one contact load point from the car.

Did a bit more searching and found this quite useful thread with pictures. https://rennlist.com/forums/991-gt3-...adapter-7.html Validates using a torque multipier. I think I will just want to calbrate test it against a big 3/4” direct torque wrench at the first use, or use a torque adapter one-time.

 

Centerlocks need to be torqued off the ground with no load. Rears are held pretty well with the parking brake, how about the fronts turning without someone in the car pressing the brakes? And torque multiplier has 1/2" input with 3/4" output?

 

^Torque multipliers work fine with a clamp on the brakes. The reaction arm on the ground helps to keep the front wheels from turning although they can still turn if you aren't careful, but easily avoidable. There is theoretically a loss of accuracy but it's nothing to worry about and others that tested torque multipliers found little error in practice. If you are the worrying type just set your torque over by the max error of 3 to 5%.

 

Two considerations to using a torque multiplier:

First, they come in a wide range of qualities, which translates to accuracy. There are very high forces inside, and losses can be significant and non-linear with applied torque. If you want to go for a non-motorsports grade unit, I'd suggest confirming the results with a digital torque gauge at the output over time to learn the resulting accuracy. Given that you have only one condition (440 ft-lbs) you're wanting to achieve, this could get around the non-linearity problem.

Also remember that torque multipliers have maximum torque limits, which you must not exceed or they will be damaged. Also, removal torque can be significantly higher than application - I've measured as high as 840 ft-lbs on my car. (This is another reason to not over-tighten the nuts.)

You'll want to consider the length of the reaction bar carefully, since in a home/track/roadside scenario the jacking height may be different.

Finally, I suspect using a reaction bar against the ground instead of the wheel likely eliminates the advantage of not accidentally turning the steering wheel while using the tool.

So some considerations, but it seems like this could be a workable solution.

 

happened to me today on one rear wheel ... was a bit tricky to get it out but I managed - now trying to get the damn circlip back into the nut!

 

I had 3 separate on me last time. I got them back together after rejoining the soccer paste from the not and female taper of the wheel. Fireman had only 1 come apart at the dealership. I think the key is the have a new, think layer on the nut and wheel. Peyote to my 3 separating I had the wheels of twice per year for about 2 years without issue.

 

I didn't find the circlip that hard to put back on - once I figured out the trick to separate the thing it is pretty easy. Are you perhaps reconstructing it incorrectly? I know there are plenty of pictures of the nut exploded (and where to put the paste - if you clean the entire thing) but it shouldn't be that hard to put together.