Checkpoint “pulling” into turns
 

Hi all — I recently got a Checkpoint SL7 that I really love. I’m coming to it from doing either exclusively road (where I run 28s on a Roubaix) or mountain biking (Top Fuel and Farley). I’ve never ridden a gravel bike for any extended period, and today I took it for ~25 miles and noticed two things that may or may not be related.

1) when I lean to turn, the bike “pulls” in the direction I’m going. Unless I counter-steer, the bike’s handlebars would go too far and I’d wreck. It was disorienting the first handful of times, but I’m getting the hang of it. Is this a characteristic of the bike/gravel bikes in general, or is this something that indicates an issue? I noticed this once on my Top Fuel when tire pressure was low, but otherwise have never experienced this before.

2) aggressively engaging the front brake vibrates the whole front fork/handlebars — so much so that my Garmin watch thought it detected an incident and texted my wife this morning on my commute :D I’d installed a PDW front fender last night, but it’s thru-axle so I can’t imagine I didn’t seat it properly or something — all seems well and the wheel is on tight enough.

Insights appreciated!

Cheers!

https://cimg5.ibsrv.net/gimg/bikefor...9daf474b8.jpeg

Before reading your reply I thought to myself it could be the angle of The handlebars and maybe rotating them down would provide more consistent control on turns.

I might be inclined to unwrap, rotate the bars down, move shifters up and rewrap. That’s where I’d start.

Check that the headset and stem are tightened appropriately and gauge to see if front rotor is true or if all bolts are tightened to spec on the caliper and mount.

Interesting - I did tilt the handlebar up (mostly b/c I prefer a slightly more upright position commuting). Is that something that could affect cornering though?

I converted it to tubeless and tire pressure is around 30 psi — definitely feels softer while riding, but I can’t really notice the tire deforming when there’s weight applied.

Interesting. Makes sense - I can try rotating it down a bit. This wouldn’t affect braking though presumably, though, right?

Edited my post to include more. If you rotate bars down and move shifters up it will effectively decrease the reach and might provide enough of an upright position.

Interesting about the weight on the front wheel! I’ll have to remember to pay attention to that.

As best I can tell, everything is tightened properly. I actually took the bike in this afternoon to a Trek shop to have them look at the brake/vibration thing, but it started raining and they couldn’t test it - policy about riding customer bikes in the rain. But they did say everything looked good after taking the wheel off and making sure things were torqued to spec and so on.

I’ll see what happens next time I’m out, and will try rotating the handlebars down a bit to see if that helps with the pulling into turns.

Thanks folks!

A disc fork can shudder because the headset is not properly tightened. It can also shudder because the disc rotor is not properly bedded in or because of uneven rotor wear. And if the brake caliper isnt properly tightened, that too will cause fork shudder(and eventual damage).

As for the handlebar setup- you do what you need to make the bike fit, but when the bars are pointing up to the sky like that it sorta makes drop bars pretty pointless since you cant easily brake from the drops. The ramps and hoods being set up flat with the ground allows for a rider to easily access the tops, ramps, hoods, hooks, and drops.
If you need the bars to be higher up and closer to you for a more upright riding position, maybe get a positive rise stem which will do both things. Or new bars with shorter reach can help too, plus there are bars with 20mm of rise from the center clamp to help get the bars up higher.

A bike that pulls into a turn more than you want could be due to a low tire. It could also be due to frame geometry you arent use to(though with you riding road and mtb, you already ride the extremes of geometry) since a gravel bike's trail is going to be higher than a road bike.
The larger a fork's trail, the more readily it will flop into a turn when you lean.

I dont know your bike's frame size, im guessing 54 or 56, but either way the Checkpoint's trail in those sizes is not high compared to many other offerings on the market right now. It would most likely be between your road and mtb.

Wow, thanks for this - lots of great information. Yep, the bike is a 54 (according to Trek, I’m right on the border between 54 and 56, but my road bike is a 54 so opted for that). It’s a good idea to look at the riser stem and drops - will for sure look into this, esp since the Roubaix road bike I normally ride has both and I don’t have the drops angled up nearly as high.

I've had the front tire pulling into a turn - for me it was my front tire losing air.

should have sized up to 56 but change to a 80mm stem you bike will be 20mm higher and 5mm shorter, the bike will also be more stable and less toe overlap with fenders

I actually rode both of them but the 56 felt *way* too big - even the 54 was a bit of a stretch compared to the Roubaix. That said, it's still within the 30 day return window so if I find it's a big issue I can always go back.

93mm reach handlebar also does not help

Yep, after looking for a riser drop bar I noticed how long the reach is on the Bontrager bar. I might just replace the drops on the Trek with the same ones that are on my Roubaix - which are shallower and rise a bit. Looking into (safe) bike fit options in the area right now where I can actually work with an expert on all this stuff!

You could try adjusting the horizontal sliding dropout, from the pic it looks like you have it all the way forward. Longer wheelbase = more stable.

Post #9 by mstateglfr covers all of the likely possibilities, I think.

You definitely should angle all those bars down. That is not the way to get shorter reach.

Agree with mstateglfr, low tire pressure. Nice bike, that's a hell of a commuter.

Ha, thanks, yeah, I did angle them back down. I'll do a proper fit and probably replace bars & stem at some point once it's safer to do.

Thanks! It's def used for commuting, but also pleasure :)

This is a good idea. I think the tire pressure is good, so this + perhaps just getting more used to the wider/knobbier tires on a road-ish bike.

I just changed out the OEM tires on My SL 5, same as your SL 7tires. With SCHWALBE Marathon Supreme HS 469 and I can unequivocally say, it is the OEM tire causing the pulling into the turns.

My average speed over the same completely unscientific 8 mile course was up more than 1 MPH to boot.

Ah! Yes, thanks for this! I forgot to follow up to this thread actually. Two things helped in my case: running much higher tire pressures with the GR1s, though even then there was a bit of pulling. But secondly, as you mentioned, replacing the tire in the end made the problem completely go away. The SL7 got bad puncture on a commute a few days ago and had to be replaced (though running tubeless got me a couple miles to the shop before all the air was out). Since the front tire had to be replaced, I decided to swap to slicks (Bontrager R3 32s) and now the pulling is completely gone. So it was indeed the tire. The R3s are so far quite nice, and comically fast compared to the GR1s, though I do fear I'll end up with a puncture eventually on them as well. I'll have to give the Schwalbes a look when the time comes.

The other issue I mentioned upthread, about the vibration when heavily braking, just worked itself out -- it doesn't happen anymore. I think it must have been something on the rotor or unevenly worn pads or something that have now worked itself out.

I should have mentioned I put on the 40mm SCHWALBE Marathon Supreme HS 469.

I don't think the issue issue of pulling into turns has to do with how high the bars are.

That said, if you want the bars higher or closer, I would just flip the stem up (or use a different one) instead of angling the bars up like that. But do whatever is most comfy and works.

Thanks, yeah, pretty certain the pulling is from low tire pressure/knobbier GR1 tires. I was wondering about flipping the stem -- is that something that can be done safely? I've already put the bars down a bit, but I'm still stretched out a bit. Flipping the stem seems like an easy thing to try while waiting for it to be safe to do a real fit. I might give it a whirl if it's easy enough.

Yep. perfectly safe.