Senton Suspension Tuning Question

[chrisdev01]

After a 15 year hiatus from RC, I recently purchased a pair of Senton 3S RTRs.

I have been running the cars exclusively at my local track. The track is hard, dusty, outdoor clay which is not frequently maintained. The front straight is pretty bumpy.

I’m having a problem with the rear end bouncing while running down the straightaway at high speed.

So far, I have done the following, which has helped, but I think it could be better:

1. Upgraded to Proline Powerstroke shocks
2. Installed the green soft springs in the rear
3. Kept the yellow medium springs in the front
4. Currently running 30wt shock oil front & rear
5. Verified no binding in shock travel
6. Verified no binding in suspension travel
7. Reduced rear pre-load via collar adjustment

The two things that seemed to help the most was the soft rear springs and the decreased preload.

Should I increase the shock oil weight to 40, or decrease the shock oil weight to 25?

Another option might be to use a different shock piston - not sure if Proline sells different pistons for the Powerstroke line?

Anyone else experience this? If so, how did you resolve the problem?

Any suggestions would be greatly appreciated!

 

[Diem Turner]

I don't have any suggestions for you because I don't have that vehicle, I just wanted to welcome you to the forum!!

I'm sure others will chime in with more useful information.

Great to have you aboard!!

 

[gotnitro]

Problem your having is there is no time for the rear to fully rebound due to the soft springs vs. how fast those bumps are coming. Now the a$$ end looks like it’s dragging. I’d go with a lighter oil in the rear.

Ride hight has everything to do with the way she goes down the track too. Set your preload to where the rear dog bones are just under flush toward the ground. In other words, you want the chassis just a tad under flush to the ground.

You could also try a softer tire, not compound but foams with larger sidewalls. Maybe an 1/8 buggy tire would help.

Some of that is going to happen naturally, most is unavoidable at speeds but it sounds like you’ve got it pretty dialed in already and nothing beats trial and error.

I don’t own a senton but I raced for many years.

 

[chrisdev01]

Gotnitro - you made some good points. I failed to mention that I tried the ATK (17mm hex) GridIron 2 1/8th scale buggy tires which have a small / short sidewall. This shorter sidewall made the problem worse, so I went back to the RTR tires and wheels.

My rear pre-load is currently set to have the rear A-arms slightly less than parallel to the ground. My rear ride height is 13.33mm, and the front is 16.51mm.

I might also add that I’ve seen Losi SCTE cars running 27wt in the rear, and those cars do not exhibit the same problem. I’m not sure that is really relevant though considering the fact that the SCTE weighs about 1 lb less than my Senton.

I think I’ll try the 25 wt oil and some softer tire foams. I’ll report my findings here after my next track day.

 

[chrisdev01]

Gotnitro - you made some good points. I failed to mention that I tried the ATK (17mm hex) GridIron 2 1/8th scale buggy tires which have a small / short sidewall. This shorter sidewall made the problem worse, so I went back to the RTR tires and wheels.

My rear pre-load is currently set to have the rear A-arms slightly less than parallel to the ground. My rear ride height is 13.33mm, and the front is 16.51mm.

I might also add that I’ve seen Losi SCTE cars running 27wt in the rear, and those cars do not exhibit the same problem. I’m not sure that is really relevant though considering the fact that the SCTE weighs about 1 lb less than my Senton.

I think I’ll try the 25 wt oil and some softer tire foams. I’ll report my findings here after my next track day.

UPDATE:

I switched to Duratrax Posse SC tires in their C2 (medium) compound and put 25wt in the rear shocks. Wow, what a difference. The rear end bounce down the rough front straightaway has been nearly eliminated.

If you are experiencing rearend hop on rough terrain, I found the green proline springs for the Powerstroke shocks, 25wt oil, and no preload to be just the ticket. The difference in the way the truck handles is night and day.

Thanks to Gotnitro for the excellent advice.