Pace frame design problem? HELP « Singletrack Forum

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Pace frame design problem? HELP

22 posts & 14 voices | Started 1 year ago by retro83 | Latest reply from Twodogs

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retro83 - Member

Morning all

I've got an RC405 which came with a Monarch rear shock. It's nice to ride but has a bad problem with bottoming out on any medium sized hit or jump (says in the manual it's suitable for 'all mountain' use with some jumps).

Also the rockers hit the mount on the seat tube sometimes when it bottoms out and has chipped the paint.

Here's the shock ratio (for the RC506 actually, think it's probably very similar though). I think the steep falling rate accounts for the bottom outs I'm seeing (running 15% sag - still getting them!)

here's a pic somebody else posted on the thread I made about this on MTBR
(mine looks very similar )

Is there any comeback about this sort of thing? Or do I just have to keep riding it and hope it doesn't crack.

Anybody else have this problem with an RC405 or 506?

Really annoying because apart from this issue, the frame feels great to ride

Posted 1 year ago #
trout - Member

that one is easy for pace to wriggle out of

Posted 1 year ago #
bigyinn - Member

I'd be getting in touch with the shop you bought the frame / bike off. Theres no way that should be happening!
Trout, expand please (I KNOW you love Pace's! lol)

Posted 1 year ago #
willv - Member

Ran mine (its got the DT shock) with the recommended sag and its ok but wasnt getting all the travel. I let a wee bit of air out and the brace across the seatstays clobbered the seat tube. Put another few psi back in and all was well-getting all travel etc.
I spoke to PACE about it and they obviously said it shouldnt if you run it right. They could fit a stopper in the shock if i liked to run it a bit softer than most.
Incidentlly the frame cracked at the welds (very fine hair line but there) on the shock brace after 9 months and the replaced the front end no problem.
Its got 6 months left on the 2 yr warranty so i am keeping an eye out for anymore and will be getting it replaced before the warranty runs out i fthey come back.
really like the bike as it lets me do everything on it (spain trips, xc races, Ae enduro, 24 hr etc)

cheers
will

Posted 1 year ago #
retro83 - Member

willv - Member
Ran mine (its got the DT shock) with the recommended sag and its ok but wasnt getting all the travel. I let a wee bit of air out and the brace across the seatstays clobbered the seat tube. Put another few psi back in and all was well-getting all travel etc.
I spoke to PACE about it and they obviously said it shouldnt if you run it right. They could fit a stopper in the shock if i liked to run it a bit softer than most.
Incidentlly the frame cracked at the welds (very fine hair line but there) on the shock brace after 9 months and the replaced the front end no problem.

I reckon the DT shock has a tiny air chamber, and the falling rate on the frame is to counter-act this. Somebody on the MTBR thread I linked above is the same weight as me, and uses half the PSI I use in my shock!

Also that's not a great solution to the problem. They really shouldn't need to reduce the travel available in the shock to stop the frame bottoming out before the shock does. That's always going to cause problems further down the line.

Disappointing

Posted 1 year ago #
ginsterdrz - Member

How glad am I that I didn't purchase a 405 or any PACE frame for that matter.

I was seriously interested in the 405 but alarm bells started ringing when the claimed weight was 1lb over that advertised by PACE. Couldn't find one to test and have only seen one in the flesh so far.

Now there are two or three threads running with frame crack issues as well as the linkage problem.

Posted 1 year ago #
retro83 - Member

ginsterdrz - Member

How glad am I that I didn't purchase a 405 or any PACE frame for that matter.

I was seriously interested in the 405 but alarm bells started ringing when the claimed weight was 1lb over that advertised by PACE. Couldn't find one to test and have only seen one in the flesh so far.

Now there are two or three threads running with frame crack issues as well as the linkage problem.

Well I'm double pissed off because I sold the only 2008 Commencal Meta 5.5 which didn't crack to buy this frame!

Posted 1 year ago #
DezB - Member

You don't mention what Pace say.. do they want you to ride it until it cracks? Do they have recommendations for the shock tuning?
One thing, if the frame is still under warranty, DO NOT make any modifications or changes to shocks without checking with Pace first. Or they will wriggle out of it.

Posted 1 year ago #
epicyclo - Member

That's simply bad design.

Posted 1 year ago #
retro83 - Member

I haven't spoken to them or the shop yet. Wanted to get some opinions on here first. Wasn't sure if I just needed a bit of the MTFU treatment.

Posted 1 year ago #
jim the saint - Member

It shouldn't matter how much air is in the shock, if the rocker bashes into the frame when there is a shock attached then there is a problem with the frame.

If I was Pace I'd be a bit nervous. Unlike seat-tubes failing this is very easy to demonstrate to Trading Standards that the frame is not fit for purpose.

Posted 1 year ago #
PeterPoddy - Member

That's simply bad design.

Yup. I agree. Or a fault.

Whatever they say, you can buy a whole bike for the price of that frame alone from another manufacturer that won't have that problem. For that money, I'd expect more.

Posted 1 year ago #
retro83 - Member

PeterPoddy - Member

That's simply bad design.

Yup. I agree. Or a fault.

Whatever they say, you can buy a whole bike for the price of that frame alone from another manufacturer that won't have that problem. For that money, I'd expect more.

Indeed.

DezB - Member
One thing, if the frame is still under warranty, DO NOT make any modifications or changes to shocks without checking with Pace first. Or they will wriggle out of it.

I will check when I'm home from work, but I'm fairly sure that the manual mentions the shock sizes and so on in case you want to replace it. Don't recall it saying anything about using specific shocks or tunings, but yes that is a good point.

The other thing is that even if the shop agreed to replace the frame (unlikely I suspect) I don't think it would do any good. Unless they have revised the rocker arm so it's a few mm further away.

Posted 1 year ago #
hora - Member

Sale of Goods act. Manufacturing defect etc.

Posted 1 year ago #
Paceman - Member

Here's the shock ratio (for the RC506 actually, think it's probably very similar though). I think the steep falling rate accounts for the bottom outs I'm seeing (running 15% sag - still getting them!)

Incorrect sag is your problem. The manual which comes with a new RC405 frame specifically says sag should be set at 10mm, not a percentage range of sag like you might use with a Fox RP23 etc.

I've had no issues in 18 months with sag set in this way (DT Swiss Shock). Bottomless travel from the free floater design which feels much like VPP etc, and no need for any platform damping.

Posted 1 year ago #
retro83 - Member

Incorrect sag is your problem. The manual which comes with a new RC405 frame specifically says sag should be set at 10mm, not a percentage range of sag like you might use with a Fox RP23 etc.

I've had no issues in 18 months with sag set in this way (DT Swiss Shock).

Thanks, but I don't think that's true; 10mm of 50mm = 20%. I'm running 15% = 7.5 mm - so that is less than Pace recommend and I'm still having the problem.

Also regardless of the falling rate problem, the rocker should never hit the frame.

Bottomless travel from the free floater design which feels much like VPP etc, and no need for any platform damping.

Given the subject of the thread, are you taking the mickey?

Posted 1 year ago #
Paceman - Member

Retro83

No mickey-taking intended, i've genuinely had faultless performance from the 405 suspension platform. I can only assume there is either a problem with the RS Monarch Shock or a defect in your frame.

I'd be having words with the dealer you got the frame from in the first instance.

Posted 1 year ago #
fattatlasses - Member

FWIW, I had an RC405 (large frame w/DT shock) and never had the exact problem that you're having. I used to run 10-11mm sag - initially the shock did have a more 'bottomless travel' feel, however, there was a problem with the damper on my shock (I just thought it was normal to sound very squelchy :?. ) After the shock was serviced it got more of a pedal efficient and progressive feel (which I didn't mind too much) and it was silent.

I'm wondering if your shock might benefit from having the compression damping tweaked?

As far as the rockers hitting the frame though, that does sound a pretty bad design oversight. Although I guess that if the shock is performing properly, this should never be a problem, even with a little more sag than the 7.5mm you're currently running.

Certainly sounds like there's a problem with the shock you've got, so I guess your first port of call is going to be the shop that you bought the frame from. Reckon you should be looking to get a free shock service - by someone that knows what they're doing with RS shocks, like TF Tuned.

Best of luck with it (be interested to knwo how you get on).

Posted 1 year ago #
retro83 - Member

Retro83

No mickey-taking intended, i've genuinely had faultless performance from the 405 suspension platform. I can only assume there is either a problem with the RS Monarch Shock or a defect in your frame.

I was only kidding. I don't think it's the shock as such - it's more that it just cannot offer the rising rate that the DT swiss one has. It's just a much more linear shock. I think the DT one might feel harsh on a 'normal' (linear or rising rate) frame.

fattatlasses - Member
I'm wondering if your shock might benefit from having the compression damping tweaked?

I was considering that, but frankly I can't afford the £125 to get TF tuned to revalve or Push it at the moment. I've spent all my spare cash on this frame over the last six months and now I just want to ride the thing without worrying about which bumps I can hit

As far as the rockers hitting the frame though, that does sound a pretty bad design oversight. Although I guess that if the shock is performing properly, this should never be a problem, even with a little more sag than the 7.5mm you're currently running.

I'd be interested to see if somebody with the DT shock lets most of the air out of their shock and (VERY GENTLY!) compresses the suspension if the rockers would touch the frame at all.

My guess is now that the DT shock offers probably 49 mm of travel rather than the 50mm that the RS Monarch has, in addition to the rising rate (small chamber) design so it's not a problem anybody with the DT shock will probably witness.
EIther that, or the i2i length on the DT is slightly over 190mm so the rocker is spread further apart at full compression

Posted 1 year ago #
BenjiM - Member

Any chance that the shock eye to eye is too long?

Posted 1 year ago #
retro83 - Member

Could be too short I suppse, I haven't measured it. The shock came with the frame so it's strange if it is.

Posted 1 year ago #
Twodogs - Member

Someone pointed me in the direction of this thread, and I checked mine out. I have the DT Swiss shock, and have had the bike for over 3 years (I think...just after they were first released anyway!). I've never had a problem with it bottoming out. I run about 10mm of sag, which fits right in the middle of the range recommended by DT Swiss.

I guess it's a problem with the Monarch shock not working the same as the DT Swiss (which the frame was allegedly designed around).

Posted 1 year ago #