Posts
6
Joined
9/7/2023
Location
Rossland, BC
CA
Edited Date/Time
9/7/2023 7:58am
I recently built up a 2023 Intense Tracer 29 and have noticed the driveside crank is rubbing on the chainstay under high load (i.e. pedalling up a steep incline). I've seen some forum posts where the cause was frame bearings, the crank spindle needing a spacer, and a bent crank arm. Curious based on the video if anyone has any suggestions on what could be the root cause of this?
The bike was built my a shop, and they've advised that there are no more spacers that can. be added to push out the DS crank.
Here is a link to a video - https://youtube.com/shorts/FVs8jQZS1js?feature=share
Wrong Q factor?
I would contact Intense direct if your shop is not helping. What cranks are those? Seem quite flexy.
Some frame flex is pretty normal, and I will usually allow a bit more clearance than that for this reason. If the crank was bent you would probably notice (it feels super weird!) and in that top down view you would quite clearly see if the pedal was not sitting at 90 degrees to the frame (looks good to me)
Are these the cranks supplied with the build kit? Assuming the pivots are properly torqued and there is no play there, I would be looking for a crankset with a higher q factor to give more clearance
This was one of my first thoughts but I've confirmed with Intense that a standard Sram crank with a 52 mm chainline *should* work. These are Descendent cranks that have been used on other bikes (Spec Enduro, Forbidden Dreadnought) with no issues.
Pivots have all been torqued to spec. Here is another video that shows the entire rear end moving quite a bit - I probably wouldn't be concerned about the flex except that the cranks are rubbing on the chainstay and are likely to end up causing damage.
https://youtube.com/shorts/4oAUfGrgDbk?feature=share
The initial response from Intense was somewhat mediocre (which is in line with the recent reviews I've found on their customer service). They came back with "Noted. It's really going to come down to finding the source of that movement. Either yourself or the shop would need to troubleshoot each pivot point to track down where that movement is coming from. Preferably someone who has experience with these types of issues." which seems like an unreasonable ask for a frame with 5 rides on it. Either the Tracer has a flex issue or my frame has a flex issue, but spending money to troubleshoot this doesn't seem like a great solution.
The shop also offered to do this but said before I spend money to have them check this with no guaranteed outcome to go back to Intense to see if they could suggest something.
OK that is moving WAY more than it should be! That BB pivot assembly looks like an easy source for excess play, so its possible something from assembly means it isn't clamping properly (eg grease on threads & shafts, order of tightening) but there is definitely movement there.
It looks just like older Santa Cruz VPP bikes I used to work on alot that either had worn bearings or the bearings didn't have enough preload. They sometimes feel fine in the link but once you have the leverage of the wheel added on its very easy for the parts to move relative to each other.
The bb shell assembly here (#17 and #18) has a bunch of parts that needs to be pulled together, and the wide OD/narrow spacing will amplify the tiniest bit of movement. If it was assembled dry at the factory theres not way it will be able to clamp all the parts together properly, and unlikely the kind of thing that would get pulled apart during assembly (it shouldn't need to be, but that is a reality with a lot of bike frames)
Thanks for the input here. I purchased this as a frame only and it was build at my LBS so i'm not sure if this would still apply (I can ask the shop to remove the bb and check that there is sufficient grease).
Your previous comment on the bearings was one that I read previously (there was a forum comment on a 2015 SC with this issue) and the root cause was the bearings needed to be replaced even though it was a new bike. Beginning to wonder if that could be the case here.
Hopefully its not worn, although if it "settled" in on the first couple of rides and then was running a bit loose it could have caused some wear. Reminds me a lot of the first Yeti Switch link bikes (pre-infinity) that used a large bearing for the eccentric assembly. Once these had the slightest amount of wear, or the blue eccentric parts were slightly deformed, you could never remove the play without replacing the whole lot. Also bearings need more preload than people realise- once they are under load any flex in the parts will make them easily lose contact with their races so there must be at least a small amount of tension in the unit one way or another
At a glance the intense deisgn looks much more tolerant to wear/stackup differences though so hopefully its an easier fix here
Thanks for the info here.
This is a lot more helpful than what Intense has come back with - I've provided them with the same videos that I've posted here and they haven't provided any guidance, just that it could be pivot play. They came back this morning said they don't recommend I ride the bike in it's current state, which is a frustrating place to be in 11 days after initially raising this to Intense on a brand new product.
My latest update - the movement is in fact coming from the bearings around the BB per your suggestion. If you move the wheel side to side you can feel the movement in that area with your finger. Not sure if a bearing replacement would solve this, or whether the link + bearings need to be replaced (also not sure whether play in this could have caused uneven wear elsewhere).
Not expecting much of a response back from Intense on this, but thanks for pointing me in this direction.
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