Hi don’t know if anyone can help. I have Brompton C line. Maybe for just over a year. I am noticing a wobbling sensation when I ride, especially when I go fast. I tightened the seat (replaced it with a bigger one) thinking it was that but it that did nothing. Overall the bike looks fine. Tires look good and are not flat or bent. Anyone else have this issue ?
by Positive_One_-1983
7 Comments
Did you buy the bike new? If not it could be the little nylon spacers on the rear triangle. They are a consumable item and should be replaced when they wear out. That could cause some movement in the rear triangle which might cause a wobble sensation.
If the rear triangle has any side-to-side play in the hinge then you can get the hinge replaced at a Brompton approved workshop.
If you bought the bike brand new then it’s unlikely to be the spacers but I wouldn’t rule it out.
I bought it new but I will check them anyway as I’ve had the bike a while and pretty much ride it every day. Plus I’m on the heavy side so maybe that doesn’t help 😅 thanks for the advice
Check tires, should be 60-100 psi, Brompton Junction recommend 100, they should be almost like a rock
Do you have a bag (carrying something) on the front luggage block? It’s surprising how much stability it adds.
grab the rim and push it side to side if you feel play it could be the cones need adjusting to take the play in the wheel bearings. You being heavy and have been riding it like that it could have damage. Hope thats all good.
Do you have the big reflectors fastened to the spokes, they can throw the wheel off balance.
Check the headset for play. no play is the best.
Also check the 2 hinges for the frame fold, no play is the best
And inspect all welds for cracks.
Don’t ride it fast, until you resolve the problem
Had the same on one of my old Bromptons. Turned out that the rear wheel wasn’t laced particularly well and under load it would make the rear feel wobbly. It was purchased new btw, came from the factory like that – mistakes do happen..
The headset bearings, top and bottom of the head tube, support the steering tube, of course, such that the front wheel can be turned. If the headset top locknut has loosened, then the headset top cap bearing race can twist away from the bearings, which than allows the steering tube to wiggle some. Wiggle in the steer tube, can cause wobble when riding the Brompton.
In the millionth Brompton video, starting at 6:30, the mechanic begins working on the headset.
https://youtu.be/qzO6RyKAspc?si=0Z0T3Q2X8hC8eMSc