Mulleting a 29er, is there a formula to work out reach ?

Trigonometry innit. Possibly. 

But getting to the point of finding out the answer would probably be way more hassle than just bunging a wheel in, riding it and not worrying about the numbers.

If you were to calculate it, I'd imagine it would be (relatively) simple enough to work out the difference the wheel would make, but the flip chip would be a bit of an unknown.

I'm going to hazard a guess at 5-10mm though - just roll your bars forward a bit maybe?

This is a great site for a play with numbers:  https://www.bike-stats.de/en/

Just ride it and see if it works, the reach figure on its own is kind of irrelevant 

Just ride it and see if it works, the reach figure on its own is kind of irrelevant

But how do you know what number to put in your setup spreadsheet?

The distance between the cranks and bars doesn't change so although you lose about 10mm reach you gain almost the same in stack height. So the bike feels much the same size, it's just a bit more downhill oriented. The biggest change will be the BB height. The flip-chip in high will approximately halve the change in geometry.

The biggest change will be the BB height.

Yep, then the seat tube angle probably?

These (and the slacker HA) are the things I notice when I mullet my Bird anyway.

Suck it and see.

I haven't mulleted anything but my original Spitfire had +/-10mm height at the rear axle with moveable dropouts, which is basically the same as a mullet change without a flipchip to compensate.

I remember I could go from neutral to high/steep or neutral to low/slack and it would feel fine (and different in the obvious ways). When I went all the way from low/slack to high/steep the saddle position and angle needed adjusting as did the bar height/roll (but I'm annoyingly hypersensitive to this stuff). The head angle and BB height have their pros and cons either way (but I usually prefer slacker and lower, like everyone else!)

not sure why you think reach would be effected.

as others have said bb drop, effective seat tube angle would be more of an issue. it'll be forever hitting pedals on the ground so you need to resolve that either by steepening it with the flip chip, longer stroke shock etc or using shorter cranks.

not sure why you think reach would be effected.

Because i'm not the font of all knowledge, hence asking the question.

it’ll be forever hitting pedals on the ground so you need to resolve that either by steepening it with the flip chip,

Like the one i mentioned ?

you're a cranky sod arent you.

you’re a cranky sod arent you.

Not really. I was asking a question, i felt your answer was dickish.

General rule of thumb for this is:

All angles approx 1 deg slacker

BB 12-13mm lower

Reach 12-13mm shorter

Stack approx 9mm taller

Thanks @cy

I think 12-13mm lower on the BB would be too low, so i think i'd need to use the Flip-chip to compensate accordingly. Reach i'd be OK with on it's own, but i'm assuming once i use the flip-chip that would be somewhat negated. Just an idea i'm throwing round my head at the moment. But seems like maybe it'd work.

Not really. I was asking a question, i felt your answer was dickish..

Nope, you are cranky. For sure.

@weeksy Looks like Minolink adjusts the BB up 6-7mm depending on model, so you're looking at about halving those changes I mentioned above. Should probably work OK assuming your cranks aren't too long.

170 cranks on there, so not quite as long as we can go, but not short either. Worth a try at some stage anyway

If you’re going to do it anyway then just measure it.

the main things are that the SA and HA will be slacker (not necessarily a bad thing depending on original geo) and the BB and pedals will get closer to the floor.

the main things are that the SA and HA will be slacker (not necessarily a bad thing depending on original geo)

Looking at the pics of the Trek in Weeksys bike thread, it seems to have a pretty slack seat angle already. The HA looks quite steep though, so that may be improved

HA is 66

SA is 75

Although mine does have a 150mm fork instead of 140 but as to how that affects things, I have no idea

I have a slash which I mulleted and the only think I changed was the link to high. No issues with pedal strikes. Feels pretty much the same angles wise. <br />For me it rides much better better though. Less catching the rear wheel on steeps and feels more agile in corners. 

HA is 66

SA is 75

Not too front steep/rear slack then, must just be the angle of some of the pics 👍

I have a slash which I mulleted and the only think I changed was the link to high. No issues with pedal strikes. Feels pretty much the same angles wise. <br />For me it rides much better better though. Less catching the rear wheel on steeps and feels more agile in corners.

I believe the race team all did this to the Slash and loved the mullet, but then worked out they were going a bit slower - so they ride full 29 but maybe pick a shorter frame for agility.

As we're not pro enduro racers, we can just enjoy the bike that feels more fun though, eh.

I love being able to quickly switch my bike from 29 to mullet - and both ride great and have their advantanges 😀

Mine isn't really related to speed... more just 'something to do over winter' and having a bit of a play really. It's somewhat negated by the fact that yesterday the trails were getting a bit drier, however once again they're drowned this morning, so all a bit pointless worrying.

I borrowed a wheel off a mate, but i'm not sure there's much point even trying it at the moment. So i think i'll go bleed some Tektro brakes on the wifes Eeb 😀

Doing a quick sketch and maths you need to work out from your tyres and wheelbase length how many degrees you think you're dropping the toptube by , then I think your new reach is old reach * cos of the angular change. It's not much tho' , couple of mill, the real difference being the rotation and the stem/bars going up

something to do over winter

How about fitting the wheel and riding it?
You could even measure it if you think it'll make a difference to the outcome...

How about fitting the wheel and riding it…

Well yes... But why can't i ask questions here too ? There may be interesting points that come up for people who are thinking of mulleting their bikes too.

Have you actually measured the bike as a full 29er, or just relying on what Trek say it is?

But presumably since you're doing it for to see whether it rides 'better', the numbers are irrelevant anyway.

I've ridden full 29ers for years and so had most of my riding pals but since we moved to ebikes for the enduro stuff they've all gone mullet whereas I'm still full 29er.

Simple view is that I struggle to stay with equivalent-speed pals on tight stuff and they struggle to stay with me on fast/open stuff.

There may be interesting points that come up for people who are thinking of mulleting their bikes too.

Then you'd be in a position to tell them what differences [b]you[/b] felt...

Then you’d be in a position to tell them what differences you felt…

1. As we've seen 'feel' isn't a strong point of mine, which admittedly may negate the whole discussion
2. It's raining... like horrible, cold, wet.
3. I'm working
4. It's a discussion forum... That's kinda how they work. As per a couple of posts, some have tried on Slash's, some have tried and found the downsides, some have noticed the BB height difference... Lots of little snippets of information. As i say, it's a discussion forum, that's kinda why we're here. It's more interesting than discussion politics to me that's for sure.

I wouldn't know the exact reach on any of my bikes tbf, but know it's generally quite short - so the Ragley may be an eye opener.

Get on it, does it feel right? Yes, go ride, no, go ride anyway, adjust something to suit for the next ride

‘feel’ isn’t a strong point of mine, which admittedly may negate the whole discussion

My point exactly.😉

It’s a discussion forum… That’s kinda how they work.

They work much better when folks post about their actual experiences rather than asking questions they have the means of finding the answer for themselves.

Loads of people have already posted up [b]their[/b] experiences on the subject. Myself included.
You have the wheels and a bike. Ride them and tell us what [b]you[/b] think.

I mulleted my FlareMax to make the back end more manageable. I didn't bother changing the headset for an angle set jobby mainly because I didn't want to spend the money. I gave up trying to measure the geometry on the garage. It feels slacker and shorter - both of which I  wanted. I've not had any issues with pedal strikes. Either the drop isn't that much or I am better able to place the back end.

End result is a bike I now really like!

I mulleted my 650b Canyon Sender in the Summer and the result has been excellent - now has a a 61.5 degree head angle according to a mates calculations - didn't do any maths, just tried it out

Conversion was done on the existing fork (just a change of the lowers)

General rule of thumb for this is:

Wow, those numbers are way more than I would've expected! I can see why it's popular for DH bikes.

I can see why it’s popular for DH bikes.

I dunno you know. As we know, my lad is fairly handy on a DH bike, but he really struggles to prefer the 29/29 or the mullet on the Session9. He can notice a 'difference' but not really enough of a difference either way to be fully sold on either version. We currently have his set at 29/29 and he's happy. But i think on certain tracks we may go mullet.

I've mulleted my pace 529 so it's a 52927.5. BB is fine and no issues with pedal strikes. 

I feel it's a bit more nimble on tight stuff but the bigger tyre 2.4 to 2.6 actually has a nicer feel.