Would a Mullet bike set up make hitting jumps easier??

Personally unless you are a pretty serious racer or over 6 Ft tall I definitely prefer 27.5 in the rear

I ride a GT Force set up as a mullet and also have a GT Sensor which is a full 29er and find that the sensor is actually more fun on jumps. That said however, you mentioned wanting to feel more confident and the mullet definitely handles jumps a bit easier since that rear wheel never really interferes with body position. Best thing to feel more confident though is to practice and work on technique, either way good luck and have fun!

Or should I just go with a full 650B bike if I want some help with jumps?

Why'd having staggered wheel size become something to benefit lofting the bike? If anything, the bike with two wheels the same size would balance better - otherwise the bike makers would include a packet of reusable adhesive weights to make up for there having been the larger wheel, of which there is none. So, either nobody at the bike stores has jumped these bike yet, or small, adhesive weights get mired down in Commodity Tariffs and County of Origin Acts complicating legal export to other lands. Making the trails suffer.

To me - having the two different wheels shows that Mountain Bike is essentially clueless on how to sustain itself, except for XC.

What sort of jumps are you talking about? If you are dirt jumping in the traditional sense, a hardtail 26" or BMX bike are going to be best and make a really big difference for your comfort and ability compared to the Sentinel you're riding (not that they can't be done on a Sentinel, but it's most definitely going to require a lot more effort).

If you're speaking about step downs, long doubles, drops, etc. built for mountain bikes I don't believe anything will make a bigger difference than riding more and getting used to moving your body and bike around in the air. The best way to get comfortable with the relatively small amount of control you have in the air is by riding jumps of all sorts of shapes and sizes; experimenting with the different speeds and the different techniques required to land them smooth and in control.

A new wheel size is not going to make much of a difference in comparison to the creative practicing of jumps, going fast one run, slow the other, nose high, nose low, whipping left and whipping right, turning your head mid-air, taking off a hand, using the rear brake to bring the front end down, landing into corners, taking off from out of a corner, etc. There is a whole ton of practice that can be done that's "free" before looking to change wheelsize. My favorite things are jumping into/out of a corner and going progressively slower until I can no longer clear the gap (this one gets exciting as you will have to keep the front down to gain the extra few feet and it's easy to OTB after a hard bunnyhop while attempting this and not quite clearing the gap)

astrizzle wrote:

Or should I just go with a full 650B bike if I want some help with jumps?

Just go w/ 650b at both ends unless you respond if hearing someone yell 'Hoss!' or can dunk a basketball on your tip toes. This 'Mullet' bike idea will get binnacled after a season - they look ridiculous.

"Would a Mullet bike set up make hitting jumps easier?" No.

No

Unless you have long femurs or is taller than 5'10, i'd think so yes... The high BB drop in relationship to the rear axle of a 29 wheel will require a little more of a violent yank to create the initial lift to rotate around that axle. That's because the BB is lower and in a position of less leverage than if the rear axle would be a 27.5 or 26.

Full suspension mountain bikes kinda suck on steep jumps, regardless of wheel size. If you're hitting jumps that are steep enough for BB drop to be a significant factor, I think you're going to be more bummed on your 2.5" super tacky tires at 25 psi and your suspension that's set up soft enough to absorb roots and trail chatter. You can set up a full-suspension bike to be better on steep jumps, but you're polishing a turd, and that's from someone who loves jumping his full suspension 29er. There's a reason why BMX bikes don't have suspension and run smooth tires at 70 psi.

I have definitely wondered if jumping a mullet would be easier. I'm about 5 foot 9 with pretty short legs, and I think it would be easier to move on the bike with a bit more space. That said, I think that would be helping on the margins, the main thing is just your overall comfort jumping. I've gone to my local dirt jumps on my Norco Sight 29 and when you're hitting proper dirt jump sets (as opposed to jumps on MTB trails), putting 40psi in the tires and 5/10 more PSI in my fork and shock makes a massive difference. I would suggest trying to set up the bike a bit more for jumping when you're focusing/practicing your jumping. This will make popping and pumping the bike easier, help you get the feel for jumping, and build those skills for when you're riding your normal set up. Plus, air is cheaper than a new wheel and link.

pohsoonteng wrote:

Unless you have long femurs or is taller than 5'10, i'd think so yes... The high BB drop in relationship to the rear axle of a 29 wheel will require a little more of a violent yank to create the initial lift to rotate around that axle. That's because the BB is lower and in a position of less leverage than if the rear axle would be a 27.5 or 26.

Good job sharing actual thought instead of an opinion.

TEAMROBOT wrote:

Full suspension mountain bikes kinda suck on steep jumps, regardless of wheel size. If you're hitting jumps that are steep enough for BB drop to be a significant factor, I think you're going to be more bummed on your 2.5" super tacky tires at 25 psi and your suspension that's set up soft enough to absorb roots and trail chatter. You can set up a full-suspension bike to be better on steep jumps, but you're polishing a turd, and that's from someone who loves jumping his full suspension 29er. There's a reason why BMX bikes don't have suspension and run smooth tires at 70 psi.

Jumping full sus vs. HT vs. BMX is all a matter of technique. Before my MS when I actually built and rode steep jumps, (And by steep I mean Nor Cal BMX style, near vertical lips and landings like the Matt Pack at Nor Cups R.I.P..), I would always test them out on my DH bike to help absorb the learning curve. Then the next time out I'd bring my proper dirt jumper. Any bike can be used on any jump, it's just a matter of adjusting technique.

Personal opinion based on multiple hours in the bike park testing:

Short version:
There is very little benefit to taking a 29er frame and going to a mullet setup.

Long version:
As recently as 2 weekends ago I tore up my 29er rear tyre in 3 places in 2 runs at Isola 2000, rather than fix it again, i swapped over to my e-bike rear wheel.
29er wheel: DT swiss e1900 (with 36t ratchet), 30mm wide, + Michelin wild something tyre 2.35 wide.
27.5 wheel: Commencal built wheel with spank rim+ 35mm wide, nukeproff ARD foam, michelin E-Wild 2.6

Bike Capra 29 in low.

Note that yes, my 27.5 setup is heavier than the 29er one, which is one issue with my comparison. There was literally no difference in ride feel, probably due to the weight and tyre size counteracting any substantial changes.


Hypothesis:

Mulleting a 27.5 frame might make a difference, as you are changing both the fork and wheel upfront, potentially (unless you decrease your travel quite a bit) giving you slacker head angle and higher stack (both good), yet you still benefit from the shorter chainstays on the 27.5 rear.

Conclusion:
Ride more, think less.

Eoin wrote:

Personal opinion based on multiple hours in the bike park testing:

Short version:
There is very little benefit to taking a 29er frame and going to a mullet setup.

Long version:
As recently as 2 weekends ago I tore up my 29er rear tyre in 3 places in 2 runs at Isola 2000, rather than fix it again, i swapped over to my e-bike rear wheel.
29er wheel: DT swiss e1900 (with 36t ratchet), 30mm wide, + Michelin wild something tyre 2.35 wide.
27.5 wheel: Commencal built wheel with spank rim+ 35mm wide, nukeproff ARD foam, michelin E-Wild 2.6

Bike Capra 29 in low.

Note that yes, my 27.5 setup is heavier than the 29er one, which is one issue with my comparison. There was literally no difference in ride feel, probably due to the weight and tyre size counteracting any substantial changes.


Hypothesis:

Mulleting a 27.5 frame might make a difference, as you are changing both the fork and wheel upfront, potentially (unless you decrease your travel quite a bit) giving you slacker head angle and higher stack (both good), yet you still benefit from the shorter chainstays on the 27.5 rear.

Conclusion:
Ride more, think less.

Yep, mulletting a 29er looks like less beneficial than mulleting a 27,5 frame. BB already low becomes too low, chainstays are longer, etc...

Mulletting a 27,5 can have advantages for sure, putting the BB a little higher from the rear wheel and lower from the front wheel = better integration "in" the bike AND easier to manual. And head angle slacker. Maybe too slack, because a 29" wheel is about 45mm more in diameter than a 27,5", so just changing wheel it makes the head angle about 1° slacker. Plus at same travel a 29" fork is 20mm longer. So An other degree slacker. Not to mention the seat angle follows the same rule.

But to answer the first question : nope, I don't think a mullet bike set up itself would make hitting jumps easier. But you'll hit jumps easier on a bike you are comfortable with, and if you are more confident on a mullet bike so yes, it would make hitting jumps easier.

Yup, I didn't want to get into the numbers, as you need to factor in angle of the fork etc... But simplifying a little... (you made a slight error in taking the diameter+fork A2C, so you counting something twice)

Generally speaking: In my experience the difference in diameter between good tyre options for 29 and 27.5 is closer to 2cm.

So changing a 275er to mullet: the number affecting the axle is simply the radius (so 1cm higher), and the stack + BB are affected by the radius of the wheel + fork A2C*sin(angle), but let's massively simplify and use the wheel diameter = 2cm.
So without changing travel upfront: Axle goes up 1 cm, stack 2cm, BB (roughly 1/3 of stack increase) 2/3cm == 7mm (which is quite a lot), and your head angle will slacken at least 1degree.
This is why most people would reduce travel on the fork 1cm, to roughly halve those numbers: still get the high axle benefit in full, and a reasonable stack + head angle bump in the right direction, BB increase of 3mm can be compensated with shock tune (less sag, more progression)

Changing just the rear on a 29er to mullet: Rear axle goes down 1cm (not sure any benefit to this), BB goes down 2/3 so again roughly 7mm (again this is a lot), stack virtually unchanged 2-3mm, head angle very minorly impacted.

So if you have an older 27.5 bike and you want to give it a bit of a new life, the change could work well (I'm considering it), especially to get a fairly slacker head angle and improved grip from the bigger tyre up front.

But if you have a 29er frame, other than increased rock strikes the change will not be too dramatic (ony exception I can think of is unless a high BB is what you are trying to resolve, e.g. 1st gen enduro 29 could benefit from this)

Eoin wrote:

Yup, I didn't want to get into the numbers, as you need to factor in angle of the fork etc... But simplifying a little... (you made a slight error in taking the diameter+fork A2C, so you counting something twice)

Generally speaking: In my experience the difference in diameter between good tyre options for 29 and 27.5 is closer to 2cm.

So changing a 275er to mullet: the number affecting the axle is simply the radius (so 1cm higher), and the stack + BB are affected by the radius of the wheel + fork A2C*sin(angle), but let's massively simplify and use the wheel diameter = 2cm.
So without changing travel upfront: Axle goes up 1 cm, stack 2cm, BB (roughly 1/3 of stack increase) 2/3cm == 7mm (which is quite a lot), and your head angle will slacken at least 1degree.
This is why most people would reduce travel on the fork 1cm, to roughly halve those numbers: still get the high axle benefit in full, and a reasonable stack + head angle bump in the right direction, BB increase of 3mm can be compensated with shock tune (less sag, more progression)

Changing just the rear on a 29er to mullet: Rear axle goes down 1cm (not sure any benefit to this), BB goes down 2/3 so again roughly 7mm (again this is a lot), stack virtually unchanged 2-3mm, head angle very minorly impacted.

So if you have an older 27.5 bike and you want to give it a bit of a new life, the change could work well (I'm considering it), especially to get a fairly slacker head angle and improved grip from the bigger tyre up front.

But if you have a 29er frame, other than increased rock strikes the change will not be too dramatic (ony exception I can think of is unless a high BB is what you are trying to resolve, e.g. 1st gen enduro 29 could benefit from this)

Nope, I took the radius for the wheel. Anyway, maybe I overestimated the 29" wheel diameter.

But in the end we agree on the use of mulletting a bike.

pohsoonteng wrote:

Unless you have long femurs or is taller than 5'10, i'd think so yes... The high BB drop in relationship to the rear axle of a 29 wheel will require a little more of a violent yank to create the initial lift to rotate around that axle. That's because the BB is lower and in a position of less leverage than if the rear axle would be a 27.5 or 26.

reading through the responses... i should mention that my thoughts on the BB drop is assuming the geometry and travel and all that is the same. Not hacking a 27.5 or 29 bike and mulleting it...

Thanks guys, I decided to trade in for a 650B bike front and rear. If nothing else than to just see if it is more fun and jump worthy than the 29er. Always love trying new stuff if it don't cost too much to change!

And an addendum to the technique post... This was back in the day when both bikes were twenty six in front and rear.