Hardtail build – Cotic Bfe mullet or 27.5

Hey Hardtail Enthusiasts,

I am thinking of building up one of the last of the Bfe 27.5 frames. I have had a 26 bfe which I loved, but considering a last build with a chunky fork (so I want to max out on travel, go full stapler / geometry change mayhem every time the fork compresses). I was aware of the new Bfe coming out, but wanted to have one of the last 27.5 bikes.

So Option 1: 27.5 frame, 170/160mm fork (frame is designed for 160mm max, but it is strong). Eye on a Bomber Z1 Coil (reduce the travel from 180mm as needed).

Options 2: same 27.5 frame, mullet build, 140/150mm fork, possibly 1 degree slacker and a bit of geo adjust from the above. Fork would probably be a newer Pike 140mm or so.

For reference, I also have a 27.5 Pace 627 which I will keep for more ‘sensible’ local riding and trying to learn to jump down at the local pump tracks; it is set up 27.5 with a 150mm fork, but riser bars (38mm riser). I would run the Cotic with some lower rise 20mm bars, so happy to slightly increase BB/front of bike. If it makes any difference, I am 6’2.

Some little observations from my own messing about…

The Marz/Fox coil setup works better with less travel (there is effectively a fixed volume air spring that can ramp up too much when the fork is set to longer travel) so I’d suggest trying that at 150mm with a full 27.5 set up first. At least you can change the travel without buying any bits… drop the lowers, move spacers around, refit. You can always try longer later, but I suspect that’ll end up with unused travel, and not handle as well either.

On running a 29er front… you need to knock 40mm off the travel, not 20mm, to get the same contact patch to crown length as a 27.5 wheel and fork. So I would expect the geometry changes (and forces on the frame) to be much greater than your option 2 is assuming there.

Thanks Kelvin – would you advise going against a mullet build?

I read somewhere that the 29er – 27.5 conversion (for the same length of fork) is something like +20mm for the increase in fork length, then 10mm for wheel size. I think it isn’t 20mm as 10mm sits above the axle, 10mm below? I might be misquoting this but it made sense at the time!

Anyway, my thinking was if I went 29er front, I would probably be best to drop travel 10-20mm, ending up with a bar height that was slightly higher than a Bfe at full 27.5 160mm fork option.

is something like +20mm for the increase in fork length, then 10mm for wheel size. I think it isn’t 20mm as 10mm sits above the axle, 10mm below?

Someone else will be along to do the maths hopefully… but I can’t fault you logic! Makes sense. If correct, it still means 30mm less travel though, ie 130mm if running mullet.

would you advise going against a mullet build?

I run mullet myself, but I don’t jump. For myself, I’d grab one of the new frames to run mullet, for my riding, and put a 150mm 29er Z1 coil on that at first, and mess around with the travel to experiment. If getting the last of the XL 275 frames, I’d suggest running it straight 275 front and rear so you could try longer travel if you wanted.

One last thing… if going Z1, try and get a previous year model that’s still got the Grip damper it it… looks like new ones have gone cheap with a new Rail damper to further differentiate it from the Fox forks. The older one is probably currently cheaper anyway, as well as likely to be more durable (and sharing spare damper parts with the 36).

If it helps I have a size large 2018 BFe 27.5 (both ends) with a 160mm Lyrik, and it’s a ton of fun! I don’t feel like it needs any more travel though, its pretty slack at 160mm and I believe the geometry is not that different compared to the latest version

Kelvin – thanks and noted on the Z1 coil. I had read that. Shame Mazza have downgraded it on the latest version.

Meatsupreme – thanks, that does indeed help. Appreciate the feedback.

Doesn’t the Bfe tread on the 627’s toes, just with worse tubes? They’d be a bit too similar for me, speaking as a 627 owner running it at 150mm. I have considered mulleting the Pace though.

Chester – I have had that same inner discussion with myself.

I have also considered (a) mulleting the 627 and (b) going full 29 (I think you can do that by just moving the drop outs back, but you just can not run a massive rear tyre I guess). If I went full 29, I would probably try and not go crazy on the build (concentrating on a decent fork) and then just move all the 27.5 components over to the Bfe. I have had the 627 on some reds at BPW and then a couple of days in Whistler – it is an amazing bike – I just like a hardtail a bit too much!

Yeah, someone on here had a 29er 627 so certainly possible. I’d considered mullet as a way of raising the bb a touch as it’s very low!

Think I’m similar to you and considering what to get next but also how I can keep what I have relevant as I really like the 627 (and my Stage 5). It doesn’t help that second hand prices are on the floor so recycling perfectly good kit seems sensible but I never seem to work out exactly what the right formula is!

If I were you though I’d make the 627 into whatever you want the Bfe to be and then buy a proper 29″ hard tail. I think….

I’d go 27.5. It’s what the frame was designed for, and any tinkering feels like it’d be more effort than it’s worth in terms of actual benefits.

Plus, mullets look WEIRD.

So Chester – update is that I am likely to go 29er on the Pace. I know it was not designed for it, but plenty seem to have done it. I want to do some bike packing and think it will make a good platform for that.

Sounds like a plan, might even do the same!

If you are certain you are going to use it at pump tracks/dirt jumps/learning to jump on a regular basis I’d go 27.5 all day long. You can still run long travel and just close off the compression to it’s maximum and/or add more air for pump tracks.