Cotic Bikes Release Mullet Option

It’s an interesting one – I’m thinking 29er is something I want to try next year but I’m not wildly tall.

You don’t have to be tall, I’m 5’9″ (honest), and have been riding 29ers for a good few years. Admittedly hardtails, but they’re great. I’m not a jumpy rider, more wheels on the ground (basically because I’m fat and shit at jumping) but I just love the feel of 29ers. I’ve just bought my first 29er full suss, Nukeproof Reactor, delivered this morning so haven’t ridden it yet but I’m well excited!!!!

ads678 Full Member
You don’t have to be tall

This. My wife is 5’6.5″ (the .5 is important apparently) and has been riding a small Jeht since March. She absolutely loves it and I don’t think she’s ever mentioned tyre/arse interaction. That includes riding some reasonably steep stuff around the Tweed Valley a couple of times this year.

I stuck a 27.5 2.8 rear wheel into my FlareMax. No Angle set but TBH I am not sure I would have noticed the 1 degree.
I did notice a lot more pedal strikes
And I just hated the way it rode – prefer the 29er set up

whats not called out is the significantly slacker seat angle. 2.5 deg slacker on the small. Their geo charts are wrong.

@kelvin You’ve dropped the rear of the frame by 19mm and raised the front by 8mm (according to the stack). reach + chainstay on a small is 884mm. I make that you’ve rotated the entire bike backwards by ~2.5 deg, which should have the exact same effect on the seat angle.

Always felt like if you can put a 650b wheel in a 29er and have it work, it probably wasn’t a very good 29er- if the manufacturer says the BB can be lowered and it still works, then why isn’t the BB already at that height for 29er mode? But the numbers look sensible here…

For myself I wouldn’t want a 2.8 in a bike like this, good fun in a hardtail but I’d rather have a normal tyre. Getting a tough enough and grippy enough rear to do the job of, say, a DD DHR2 2.4 has big downsides. But going down to a 2.4 or 2.5 loses you height of course.

joebristol
Full Member

It’s an interesting one – I’m thinking 29er is something I want to try next year but I’m not wildly tall.

Katy Winton raced a Slash 29 for ages and she’s about 29 inches tall. Mind you she’s on a mullet now.

Nice bikes, but where is that trail in the pic of the descent with the chain rail?

I don’t think you can’t take the full 19mm at the top of the head tube. I think you have to take this dimension proportionally to the wheelbase.
ie 19 * 884 / 1,218.5 = 13.8mm

Then, following through the rest of your calculation:
sin-1 ((13.8 + 8) / 884) = 1.4° slacker at the seat tube

This means that the “Actual Seat Angle (at 815mm BB-saddle height)” for the Mullet should be 74.1° (rather than the claimed 75.0°).

Thinking about it some more, I don’t think the stack measurements can be quite right…

Without the angleset the bike would slacken by ~0.9 degrees. Using a 1 degree angleset to compensate would mean that the stack should be almost unchanged (certainly much less than 8mm).

@bikesandboots It’s near Flaine and Samoens, I took the picture. Except I’m this guiding company http://alpineflowmtb.com/ instead of Wayne’s https://www.chamonixmtb.com/ As you can see, the competition between us is totally cut-throat…

@5lab Good point about the BB dropping means the stack increases. That said, the top of the headtube ends at approximately the same height – as per my last message, and ignoring the headset having an dramatically different dimensions. This means that the seat tube would only slacken by ~0.9 degrees. Still more than claimed by Cotic, but within the range of moving the saddle forward on its rails.

What I like about this is the ability to cheaply try a mullet. Swap a back wheel and a headset and you can give it ago. If you don’t like it its 20 minutes to turn it back to a full 29er and you don’t have a mullet frame to get rid of. Also I guess you can set the bike up for the riding. Doing a loop in the Peaks then 29er. A few days up at golfie then mullet might make more sense

Always an interesting and surprisingly emotive topic this one. I will throw my tuppen’orth in; I am 5’8″ and I ride a 29er Bird AM9 in ML and a mullet Geometron G1 (medium), having previously ridden a 27.5 Bird Aeris 145lt in medium.

I am averagely proportioned, but not tall, but I can ride any of the normal wheelsize combinations (never tried anything bigger than 29, but I suspect it would be a problem on the rear for me), but I do prefer the mullet for the more extreme technical riding, primarily because it gives me just a little more arse clearance. No doubt some armchair coaches will now be frothing at the mouth because my arse should never be over the back wheel, but they’re wrong. Whether I really need the extra space is debatable, no doubt I could get used to always riding a full 29er, but why not maximise my space for manouvre? Especially if it has no practical downside that I have experienced? (I certainly don’t find the 27.5 rear wheel makes riding tehnical terrain harder and the bike corners beautifully, but a direct comparison between the two bikes is unrealistic as they are set up differently.)

It is worth noting that the G1 is set up correctly to run as a mullet and has the same BB height as the AM9 – it’s also true that I have had pedal strikes on both bikes – in reality they’re a fact of life, it’s just the frequency that changes with BB height and (like anything else in MTB geometry) it’s a compromise.

I applaud Cotic for this move, it won’t be for everyone but it is good to have the option for those for whom it works.