FlashBazbo

Bad news. I bought my Trek Checkpoint SL without riding the carbon version first. I rode the aluminum version and liked the geometry, so I pulled the trigger on the carbon version. Now that I've put a few hundred miles on the Checkpoint . . . I cannot STAND the flexy, boing-boing-boing of the isospeed decoupler. Does it provide a smooth ride? Of course, it does. But it's like riding a bike inside a bounce house. Inefficient pedaling -- nothing to brace against on climbs -- and a feeling that, if I were prone to sea sickness, would likely induce vomiting. Selling the bike and returning the bike are not options. But I very much dislike the inefficiency and the continuous bouncing. So, here's the question . . .

Is there a way to reduce or eliminate the flex in the un-adjustable Checkpoint SL isospeed decoupler? Any ideas?

gus6464

The assembly is basically a bolt with 2 bearings. If it's flexing way too much maybe there's something wrong with the frame. Sadly there is no way to tune it. What did your shop say? Did they contact Trek?

redlude97

that's connected to a rubber/polymer insert. You could maybe machine something to replace that but I'd have to dissemble to see if its removable or glued in

FlashBazbo

UPDATE: I heard back from my LBS. He also called Trek to verify. There is no way to stiffen the Isospeed decoupler in the Checkpoint SL. And any "excess" flex would be due to excess flex in the frame's seat tube. Not an easy fix.

On the plus side, he's offering to work out a frameset exchange for another brand/model. Any recommendations? (I wish the Warbird V4 frameset were out!)

gus6464

So Trek didn't say that it might just be a bad frame?

Another frame option you could check out the Giant Revolt. Can take up to a 45c tire which is nice.

Planemaker

I've got a Domane and I can't imagine that much give in the coupler. Unless you are heavy or the bike is small and the seat post being extended is causing too much leverage.

I'd be checking for a defective frame.

FlashBazbo

Is your Domane the one with the adjustable Isospeed? The Checkpoint Isospeed is equivalent to the flexiest Domane setting. Therein may be the problem. It's designed to be the flexiest version. (To dispose of the other issues . . . I weigh 175 and the seat cap is pretty much in the middle of its range.)

Planemaker

My Donane is an older one and not adjustable. I can honestly say that I've never felt bouncy while riding it.

Sounds like Trek tuned the Checkpoint to be more flexible. Not the most ideal situation.

I'm sure most riders wouldn't even notice the bounce or not care. However, it does create an issue for a rider more in tune with the bike performance such as yourself.

Ald1 

I have a Domane SLR 9 and keep the adjustment in the middle. Never experienced any flex/bounce at any setting. Does the LBS have another one in stock you can ride to see if that's the "rule" not the "exception".

FlashBazbo

Word is that Trek has heard complaints about this issue, but most buyers seem to like the Isospeed. Some in the bike media mentioned the softness and bobbing in their intro articles. The one I found today mentioned the bobbing but then said that they found it acceptable. The flex is the point of the design. Not a defect.

But bear in mind that I also dislike MTB rear suspensions. I don't like the bob. I don't want wasted effort going into flexing a "suspension." But lots of people prefer the flex. That's why they make bikes in more than one flavor.

gus6464

It baffles me why Trek didn't just put the adjustable isospeed system on the Checkpoint. Especially for a bike that's designed to do it all this is where it would be most beneficial.

softreset

Pure speculation but I think it's all about the Checkpoint SL 2.0 sales. Next year's model we'll see the same configuration as the Domane and Di2 models.

Regarding the super flexy feel, I'm closing in on 500 miles (across two SL5s) and I'm north of 250 and I don't notice any bouncing or bobbing. I put just shy of 5k on a Domane 5.2 from '16 and the flex is comparable. I don't own a new Domane with the adjustable rear but the few test rides I've been on (totaling about 100 miles), the setting with the most amount of flex is considerably more noticeable on smooth asphalt riding than my Checkpoint SL.

Roger Ramjet

I also have a SL5, and I hadn't noticed any flex from the rear. Mine seems to do exactly what I would expect.

To the OP, why not get an aluminum Trek Checkpoint frame? You said you liked the geometry. I actually have recently purchased a ALR5 myself. I haven't had a chance to really compare the SL5 and ALR5, as my season here in Michigan has pretty much ended. I did get a short ride in on the ALR5, and it seems quite good, although lacking the ride quality of the SL5.

gus6464

So they gonna pull an SL/SLR and have the adjustable version on a Checkpoint SLR and charge $5k starting for it?

RocThrower

That's the only thing I can think of too. I have a Domane SL5 with front and rear isospeed, and I also don't notice any movement or bounce. It is a very comfortable and smooth riding frame compared to my old Madone.

softreset

Absolutely. Again, pure speculation but they did it with the Domane. I see no reason why they wouldn't do the same with the Checkpoint.

carlton

To the OP, Did the LBS check the torque on the bolt that runs through the bushing? Sounds like it's about to fall off. No way it should be moving around that much.

bch238

bch238

FlashBazbo

Thinking through the error of my ways . . . I definitely should have test ridden an Isospeed-equipped Checkpoint before buying one. (None were available.) But here are my thoughts on it:

Giving the Isospeed the maximum benefit of the doubt, I think it's an excellent design idea for those who ride on washboard roads. When you're going to be doing a consistently rough surface for more than 1/10 mile or so, the Isospeed shows real potential. You might get the bobbing "Green Acres on a tractor" effect, but you don't care. It's so much better than feeling the washboard that you're glad for the help! I've never ridden the Isospeed on washboard, so I'm guessing here -- but it seems like a reasonable guess. The Isospeed gives you a much smoother ride over rumbling and washboard-like textures.

Where I'm really looking for "help," though, is in the brief rougher stuff -- rocky patches in open range, stream crossings -- places where you receive a more severe shock. In those applications, I'm generally standing. And when you're standing, the rear Isospeed (or shock absorbing seatposts) does you no good. I should have thought this through ahead of time. If I had it to do over again, I would probably choose a frameset designed to flex in the rear triangle. Live and learn.

gus6464

Are you taking the LBS on the offer of getting you another frame?

softreset

Well considering the fact that all of the Domane marketing material was solely focused on the constant (smaller) chatter of the cobbles, then it sounds like the Checkpoint is behaving exactly as expected.

It almost sounds like the suspension system that Pinarello developed is more what you're interested in, in addition to the rear triangle flex.

FlashBazbo

If it works out well for everyone, I probably will. We will see. I definitely have mixed feelings. It's not my LBS's fault that I bought a bike without riding one first.

FlashBazbo

Not really. I'm not a fan of any of the pseudo-suspension systems on the market. Unless they are tunable, they can't be perfect for everyone and, ultimately, they aren't necessary. More often than not, they just introduce something else that can go wrong. Just give me tubeless tires, a Cambium saddle, and thin seat stays. Call it good.

gus6464

So the LBS wouldn't order the bike unless you bought it first? My LBS will order whatever bike I want with a deposit but I am not forced to buy it until it comes in and I ride it and satisfied.