RC10Talk - The Net's Largest Vintage R/C Community

Has anyone done this on an Old is New build?

I'm in the process of rebuilding a JRX-Pro runner. I have the stock front spindle carriers and axles from the Pro, but am limited in rims and tires. I have a ton of XXX front tires and I also have XXX spindle carriers and axles. I've drilled out the XXX spindle carriers to the right diameter to accept the JRX-Pro hinge pin. Everything lines up very nicely.

I'm just wondering if anyone else has taken this approach and were there geometry issues. I notice the bump steer will be present, but that was always something I accepted with the JRX buggies.

Rick did this with the XX stuff, and said he had a little steering issue i.e. push. I think his problem had more to do with not using the swept arms on a prose/pro wheelbase car.

Yeah, I was looking for some threads and I know Rick had steering issues with one of his Vonats build.

I always found there to be push in the JRX models to begin with. You really have to work the throttle right to get them to turn quick. I raced JRX2 way back in the day, have driven XX's and XXX's so we'll see how this does.

If you run the swept arms, I don't think the spindles carriers and such will kill the steering. Also, you can run the rear H arms in the swb position, AND space the hubs all the way forward too. That'll be all you can do for wheelbase, but with other tuning I'll bet you can do well with it. Oh you may try 25degree blocks instead of 30's also. They did make XXX ones in 25 didn't they?

I drove Rick's car set up in this configuration, I think he was running some kind of RPM front arms. I don't know if they were swept or not. But, PUSH is not the word I would describe his problem. Maybe ULTRA push. I would not recommend this setup. I WOULD recommend installing the LXT front spindles and c hubs. That helped cure a little push AND reduce bump steer.

Rick's car had the wider Jrxt RPM arms, to make up for the loss in width due to the XX spindle carrier setup. Brandon, did you and Rick try the swept arms on Rick's car? I think that would have made up most of the problem, and with your tuning knowledge I think you guys could probably have overcome any further issue. When I had a pro, it was a limousine.. but as soon as I put the swept ProSE arms on it, it woke up. I have an Ulitma Pro running the RB5 carrier setup, and deep offset HPI super stars on the front. A similar style system as the XX/XXX floating axle deal. Although there is some "side jacking" when statically articulating the steeringI don't feel that it is negatively impacting the steering of the car. I am experiencing a little push on the car, but I think that I've reasoned that down to w throw issue. (Need to move the ball stud on the servo farther out on the horn, maybe even get a large servo saver.) That said, the Ultima Pro has a significantly shorter wheelbase than a jrxpro.

I think sgirouard would be in the ballpark with swept arms, 25degree caster blocks, and rear hubs spaced forward.

Well I'm going to subscribe to the "learn through experimentation". I need to get some new springs, I have white on the front and yellow on the rear (but that's all I have outside of the original silver). Currently I'm running the original arms with XXX spindles and VLA carriers. I have to use to outer VLA hole to avoid binding but this also gives me a little bit more width. It's on a Pro chassis with H-arm rear. I have 40 (I know too thick, but I'm out of 35 at the moment) wt up front and 30 in the rear.

Does anyone have a pair of swept arms and any spring sets?