Seat cracking

[Gofer]

The seat pan on my Q-45 keeps cracking.Cruzbike has been very kind In giving me three seats .Has anyone fixed these carbon ,poly seats .My thoughts are maybe epoxy and duct tape I will try and post a pic just looking for other ideas .Thanks Greg

 

[Art G]

I haven't patched a seat like this but I did patch a C bicycle seat (DF) with a C fiber patch kit available on Amazon. It includes pieces of generic C fabric and two part epoxy. The biggest issue is getting rid of air bubbles which will act as stress concentrators and will nucleate new cracks. The epoxy needs to cure while under pressure. Unless you have access to serious vacuum equipment, you might try using a piece of medium stiff foam rubber with weights atop. I'm sure there are other, more complicated ways to apply pressure while the epoxy cures. But I doubt that the epoxy and duct tape method would give you a long term solution. I'm also skeptical of any patching because the cracks cut through the holes for attaching the seat. That means you would have to patch around the holes and I really doubt that you'll get any patch to last long. Remember that any flaw, like an air bubble, will result in a faulty patch.

Art G

 

[Gofer]

Thank you

 

[synchro]

After a couple of broken seats on my T50, I cut out a piece of 5-ply to bolt under the seat and cut some angle iron to bolt onto the backrest to stop it flexing. Riding over ramps from road to path meant that the seat had to withstand my body weight so it cracked in several places centred or starting at the bolt holes. The backrest couldn't handle similar forces so it cracked near the middle horizontally. If the backrest was left to split completely the bottom half would have hit the tyre causing a sudden stop so I'd like to avoid that.

 

[GrannyGear53]

The seat pan on my Q-45 keeps cracking.Cruzbike has been very kind In giving me three seats .Has anyone fixed these carbon ,poly seats .My thoughts are maybe epoxy and duct tape I will try and post a pic just looking for other ideas .Thanks Greg

I have the same problem. The seat that came with my Q45 developed severe cracks after less than a year of use. Cruzbik quickly shipped me a replacement seat they said was an upgrade and stronger. That cracked too. Initially I wrapped the second cracked seat in duct tape. After removing the duct tape before replacing the seat pan I saw the cracks completely framed the screws attaching it to the seat brackets. WOW! So dangerous! So, I saw no point in replacing it with the exact same thing. I purchased the older aluminum seat pan and back plate. My hubby installed it this weekend and I took it on a short test ride to see how it feels. It is a bit stiff, without any flex but maybe I can dampen the stiffness with a little bit more padding. (On the seat pan, not my butt.) This is clearly a serious quality control issue for Cruzbike. I hope @Robert Holler reads these threads and fixes this issue in the entire line before someone gets badly hurt.

 

[GrannyGear53]

After a couple of broken seats on my T50, I cut out a piece of 5-ply to bolt under the seat and cut some angle iron to bolt onto the backrest to stop it flexing. Riding over ramps from road to path meant that the seat had to withstand my body weight so it cracked in several places centred or starting at the bolt holes. The backrest couldn't handle similar forces so it cracked near the middle horizontally. If the backrest was left to split completely the bottom half would have hit the tyre causing a sudden stop so I'd like to avoid that.

Geeze! I ride my Q45 on gravel rail trails all the time. Figured it was built for that, you know with a beefy frame and suspension. Guess that’s why my seat pan cracks so frequently. This is a very dangerous design flaw.

 

[Gofer]

I also have an aluminum seat but like the carbon seat .I reinforced the bottom seat with tack cloth and a plastic repair compound mixed together redrilled the holes so far so good

 

[Flying Dutchman]

Another Q45 rider with a broken seat. I also now have the apparently reinforced version (I couldn't see any difference) and so far so good, but not done many miles on it yet.
So here's hoping that Cruzbike will continue to look into an improvement

 

[Bill Wightman]

Should not be happening but... If I had that issue I would rough sand the area on both sides (not the thru holes), jig it rigid and epoxy and glass it in about 4-6 layers per side covering an area about 1" beyond the crack and staying below the thru-hole offset. I would do that on both sides if possible without messing up the seating contour (making a bump to sit on). Then sand it all smooth and put some final coats of epoxy with black alcohol dye to match the color. Make a tape border around the last glossy coats so it looks better. Or something like that.

 

[DavidJL]

On my T50 and QX100, I cut off the cracked parts and used door hinges to make seats adjustable. But those are aluminum seats.

 

[Maria Parker]

We changed the material on the seat, which seemed to work a little better, but are still experiencing breakage. (we will continue to replace those broken seats). I think part of the problem is that the material is not consistent. Some seats seem to work really well, others break right away. Now we have changed manufacturers and they seem to know better what they are doing and are changing the design. We have not yet received those seats so stay tuned. Yes, we want to fix this!