Can you convert a 27.5 Enduro to mullet configuration successfully?

[Headshot]

Im 188cm tall and ride a 27.5 Spesh Enduro from way back in 2018. Bike works well, has a bottomless rear suspension feel, a short head tube and the geo is still relatively current. It does however have quite short chainstays, relatively compact reach for an XL and a slackish seat tube angle. So, how would this pan out if I added a 29er front wheel to the bike? With the help of a friend who went to a 38, I received a 160mm travel fox 36, a wheel and an Assegai and the testing began.  My 180 Yari had almost the same axle to crown measurement as the 36 29er fork so the bigger wheel was going to make quite a difference.

It was pretty apparent straight away that some significant geo changes had occurred. The bars were now 25mm higher at least and the HTA had slacked out to around 63.5 degrees and the BB had been raised by 20mm or so. I slammed the stem which reduced my bar height by about 10mm and added some air to the rear shock. First ride was at JH  up Irish 1-8 and surprisingly, aside from the still too high bars the climbing was quite manageable. The ride back down Armageddon went well too. I expected some negatives from the bigger wheel and higher BB in the corners but was pleasantly surprised. The front felt calmer and the grip was improved noticeably over the smaller front wheel.  The 160mm fork proved to be a winner but needed some air pressure adjustment to aid comfort. I did manage some Strava PR's on the descent.

I decided to experiment with a lower bar height and replaced the Spank 75mm bars with a narrower  38mm risers. The next ride took place at Tokai on the AM trail and DH 1 to 4. Bike felt very different with the lower than normal bars but climbing was improved. I noticed the bigger front wheels roll over on climbs - fewer hang ups on protruding rocks than I'm used to. Again, I did not notice the higher BB in cornering situations which remained confidence inspiring from a front end grip perspective. The lower bars did affect my ability to lift the front wheel but probably something I could get used to. that said I am considering some 50mm rise bars to even things out a bit better. The 36 is now in for a service and some more tweaking and testing is on the cards later this week...

[Headshot]

Okay, I think I'm on to a good thing here. Aside from some minor set up changes - tyres and shock/fork pressure, the conversion is a success. I managed PR's down the Tokai DH line this morning after several years of pretty mediocre runs down there. Bike feels controlled and jumps the same as ever, if not better. 

This conversion has given my 7 year old bike a new lease on life. 

[Martin Albrecht]

cool that this conversion has breathed new life into your bike man.

 

 It just checking, where this 2016-2019 Spez Enduros all in the 26Fat setup, so they were designed to be run either 27,5, 29er or 27.5 plus? 
 

in which chase would upgrading the rear to 29 as well not make it even more capable/ridable? And maybe sort out some of the geo intricacies of the mullet set up, especially with climbing? 

[Neill Du Toit]

I did the conversion from 27.5 plus to 29er on my Fuse but I think there might have been different frames for the Enduro 650b and the Enduro 29/6fattie?

[ALLMTB]

Thanx for this Headshot.

Ive been toying with the same mullet idea for my 2017 Transition Patrol. I worked out the actual handle bar height would only increase by 11mm if I use a 160mm 29er fork compared to the 170mm 27.5 fork I have now. The head angle would also decrease slightly. 

My worry is that the seat tube angle would then become too slack and make seated climbing worse. 

[Headshot]

7 hours ago, Martin Albrecht said:

cool that this conversion has breathed new life into your bike man.

 

 It just checking, where this 2016-2019 Spez Enduros all in the 26Fat setup, so they were designed to be run either 27,5, 29er or 27.5 plus? 
 

in which chase would upgrading the rear to 29 as well not make it even more capable/ridable? And maybe sort out some of the geo intricacies of the mullet set up, especially with climbing? 

AFAIK they are different frames 27.5 vs 29. The 27.5 has 170mm travel as well and although there is massive tyre clearance I think you'd run into clearance issues at full compression with a 29er wheel and appropriate tyre, if it would even fit. 

As I said above there are virtually no climbing issues and the benefits of the set up would be lost if a bigger wheel was fitted at the back too. My main focus is on DH performance, not climbing in any event.

[Headshot]

2 hours ago, ALLMTB said:

Thanx for this Headshot.

Ive been toying with the same mullet idea for my 2017 Transition Patrol. I worked out the actual handle bar height would only increase by 11mm if I use a 160mm 29er fork compared to the 170mm 27.5 fork I have now. The head angle would also decrease slightly. 

My worry is that the seat tube angle would then become too slack and make seated climbing worse. 

I think you need to look at your calculations again. Try and borrow a 29er fork to test the concept.

I went from a 180mm 27.5 Yari to a 160mm Fox 36. Even with the 20mm shorter travel, once you add the bigger wheel, it slackens the head angle significantly - in my case about a degree. I

The slacker STA is quite manageable on the climbs. I always ran my seat as far forward as possible anyway and with the shock in climb mode its not very noticeable. 

There is a good article on Enduro MTB mag from a few years ago re an MX conversion. I agree with most of what they say. I think the benefits outweigh the disadvantages which in my experience are minor...

https://enduro-mtb.com/en/mullet-mtb/

Edited November 14, 2025 by Headshot