300LikesTeam Associated TC4
03-21-2018, 08:31 PM
Just got back from a sweet 5 hour long practice. Sorry to say that the RPM bumper upgrade is kind of a fail. Hard to explain but there is nothing to hold the bumper (blue piece) from riding up over the rubber grommet and coming loose. I tried it both grommet on top and on bottom same problem, the bumper comes loose. Pretty irritating since you have to keep messing with it and it never stays put. Even with it on I broke a steering rack tonight. Maybe I'll mess around with it and see if I can improve it, otherwise it's coming off.
03-22-2018, 06:05 AM
There are two problems. 1) The new bumper arrangement is too thick (26 vs 23mm) to fit in the original bumpers space. 2) The rubber grommets holding the RPM bumper are super slippery semi-hard rubber and are not fixed in the bumper. (flanged on one side only) The RPM bumper itself is also very slick with rounded corners where the grommets go.
Two things happen depending on grommet position.
Grommet flange on bottom: The bumper simply slides up over the grommet, compresses the foam and is loose. (as in pic above)
Grommet flange on top: The grommet itself slides up on the bumper bracket post, stays there, and the bumper is again loose.
The only thing holding the bumper/grommets in place is the foam, and the foam isn't nearly firm enough to actually hold the bumper/bumper grommets in place after taking any impacts.
If I was a good enough driver and didn't run into things so damn much I wouldn't have to worry about this nonsense, but dang it I'm not there yet! lol
03-22-2018, 07:29 AM
Again, It's hard to explain. Yes, the two halves of the bumper do still screw together squashing everything together. No problem there other than the fact that you're squashing ~26mm of material into a 23mm space.
There are two problems. 1) The new bumper arrangement is too thick (26 vs 23mm) to fit in the original bumpers space. 2) The rubber grommets holding the RPM bumper are super slippery semi-hard rubber and are not fixed in the bumper. (flanged on one side only) The RPM bumper itself is also very slick with rounded corners where the grommets go.
Two things happen depending on grommet position.
Grommet flange on bottom: The bumper simply slides up over the grommet, compresses the foam and is loose. (as in pic above)
Grommet flange on top: The grommet itself slides up on the bumper bracket post, stays there, and the bumper is again loose.
The only thing holding the bumper/grommets in place is the foam, and the foam isn't nearly firm enough to actually hold the bumper/bumper grommets in place after taking any impacts.
If I was a good enough driver and didn't run into things so damn much I wouldn't have to worry about this nonsense, but dang it I'm not there yet! lol
There are two problems. 1) The new bumper arrangement is too thick (26 vs 23mm) to fit in the original bumpers space. 2) The rubber grommets holding the RPM bumper are super slippery semi-hard rubber and are not fixed in the bumper. (flanged on one side only) The RPM bumper itself is also very slick with rounded corners where the grommets go.
Two things happen depending on grommet position.
Grommet flange on bottom: The bumper simply slides up over the grommet, compresses the foam and is loose. (as in pic above)
Grommet flange on top: The grommet itself slides up on the bumper bracket post, stays there, and the bumper is again loose.
The only thing holding the bumper/grommets in place is the foam, and the foam isn't nearly firm enough to actually hold the bumper/bumper grommets in place after taking any impacts.
If I was a good enough driver and didn't run into things so damn much I wouldn't have to worry about this nonsense, but dang it I'm not there yet! lol
03-22-2018, 07:40 AM
Just got back from a sweet 5 hour long practice. Sorry to say that the RPM bumper upgrade is kind of a fail. Hard to explain but there is nothing to hold the bumper (blue piece) from riding up over the rubber grommet and coming loose. I tried it both grommet on top and on bottom same problem, the bumper comes loose. Pretty irritating since you have to keep messing with it and it never stays put. Even with it on I broke a steering rack tonight. Maybe I'll mess around with it and see if I can improve it, otherwise it's coming off.
Yes, I know the steering rack is supposed to be a servo saver. But by breaking in half to 'save' the servo, it just makes more work. Unless you like replacing steering racks. lol
Just a helpful suggestion.
Mark C.
03-22-2018, 07:49 AM
re: RPM bumper mount: how about a longer screw with a washer and a nut on top?
03-22-2018, 08:40 AM
Do you have a servo saver installed on the servo? If you don't, installing one will reduce the chances of breaking steering racks by about 95%. My loaner TC4 has a Kimbrough servo saver on it, and it gets the crapped beat out of it by beginners. Stock front bumper. And haven't broken a steering rack in 3 years.
Yes, I know the steering rack is supposed to be a servo saver. But by breaking in half to 'save' the servo, it just makes more work. Unless you like replacing steering racks. lol Just a helpful suggestion. Mark C.
Yes, I know the steering rack is supposed to be a servo saver. But by breaking in half to 'save' the servo, it just makes more work. Unless you like replacing steering racks. lol Just a helpful suggestion. Mark C.
I think some kind of arrangement like that would work, but don't know if I'm going to bother to mess with it any more. I'll just do the servo saver/servo saver steering rack and be done with it. Thanks for the suggestion though. If I try it I'll let you know if it works.
03-22-2018, 08:44 AM
You're right. That was my original plan, to run a servo saver + servo saver steering rack. Some folks said, "No, you don't need a servo saver, the rack is a servo saver!" so I didn't run a servo saver. I've now tried a hard/soft foam bumper sandwich, this RPM solid bumper, and the stock bumper. For all of the trouble, none of them saved my steering racks. Looks like I'll be moving the Kimbrough I have on my AMain Hobbies wish list over to the buy now list! lol Thanks!
I think some kind of arrangement like that would work, but don't know if I'm going to bother to mess with it any more. I'll just do the servo saver/servo saver steering rack and be done with it. Thanks for the suggestion though. If I try it I'll let you know if it works.
I think some kind of arrangement like that would work, but don't know if I'm going to bother to mess with it any more. I'll just do the servo saver/servo saver steering rack and be done with it. Thanks for the suggestion though. If I try it I'll let you know if it works.
Mark C
03-22-2018, 10:17 AM
Also, FWIW, since the servo saver on the steering linkage has a spring on it I thought that the small arm was designed to slip over the hump in the linkage and disengage - not break!. I thought that the recess (the V) was just a necessary and poorly designed weak spot. Kind of nuts.
Last edited by JC3; 03-22-2018 at 10:41 AM.
03-22-2018, 10:45 AM
Would a size small saver do the trick?
Also, FWIW, since the servo saver on the steering linkage has a spring on it I thought that the small arm was designed to slip over the hump in the linkage and disengage - not break!. I thought that the recess (the V) was just a necessary and poorly designed weak spot. Kind of nuts.
Also, FWIW, since the servo saver on the steering linkage has a spring on it I thought that the small arm was designed to slip over the hump in the linkage and disengage - not break!. I thought that the recess (the V) was just a necessary and poorly designed weak spot. Kind of nuts.
Mark C.
03-22-2018, 11:22 AM
03-22-2018, 12:09 PM
Would wrenching the rack down as tight as it would go and .... adding a little super glue, then add a nice servo protector work?
Does the TC3 rack have the protector? If not would that be a better rack??
Does the TC3 rack have the protector? If not would that be a better rack??
03-22-2018, 12:19 PM
Thats why I went with GPM rack.
03-22-2018, 12:58 PM
@CraigH - Thats why I went with GPM rack.
03-22-2018, 01:13 PM
The TC3 rack is a slider, but it has uses the same basic set-up as the TC4 for the servo saver with the deep v and a heavy spring...
03-22-2018, 01:24 PM
The TC4 steering is definitely a weak point. I broke mine three times before buying the GPM blue aluminum version. It broke first time out too, so don't get your hopes up that it will last.
Your best bet is the large front bumper mod mentioned earlier with the RPM bumper. Adding a Kimbrough, Xray or Tamiya servo saver might help but I find they add too much slop in an already sloppy car.
Your best bet is the large front bumper mod mentioned earlier with the RPM bumper. Adding a Kimbrough, Xray or Tamiya servo saver might help but I find they add too much slop in an already sloppy car.