Other Levo MY2018 ShortTravel 29, fork travel upgrade

[Dirk74]

Looking for advise w.r.t. fork travel upgrade for a Levo MY2018 ShortTravel 29.
Stock 29er front and rear wheel and Rockshox Revelation (FS-RVL-RC-A1) with 120mm travel.

Plan is to upgrade the fork internals to the latet version DebonAir shaft and the RC 2.1 damper.
Question is to what travel the air shaft should be upgraded.

The bike riders are my sister-in-law and my brother. The bike was originally bought for her to accompany him on XC tours. That's still one use case.
The new second use case is that he uses this bike to ride heavier stuff freeride down the hill, as he only owns a XC bike with XC fork and small rims (and a BMW 1200 GS Adventure but that's a different story).

He like to upgrade to 160mm travel (of course).
I worry that this could make the bike wonky and would say to go to 140mm travel, also to retain adequate handling for the first use case, XC tour.

What's your opinion for this case?
140 or 1600mm?

(buying an other bike, selling a bike or buying another fork is not really an option here)

 

[Wiltshire Warrior]

I'm not sure that its worth faffing about as in the last month I got a RS Gold 35 (150mm) for £320 and a Yari for £375 (160mm) both 29ers from Wiggle

So if you flog your Revelation for say £200 then you could be a spanking new fork for the price of the upgrades!!

 

[kawamaha]

What's your opinion for this case?
140 or 1600mm?

1600mm is bit too much but 160mm is fine. The frame of the ST and the "normal" Levo is the same. They put in a 120mm fork but let the shock length at the same (197mm), so the ST got a steeper head angle. (ST: 67.4° - FSR: 66.1°)
Putting in a 150mm fork will change the ST-Geo to a normal -Levo Geo. 10mm more (160mm fork) is IMHO ok, too...

 

[Dirk74]

1600mm is bit too much but 160mm is fine

The frame of the ST and the "normal" Levo is the same. They put in a 120mm fork but let the shock length at the same (197mm), so the ST got a steper head angle.
Putting in a 150mm fork will changing the ST-Geo to a normal -Levo Geo. 10mm more (160mm fork) is IMHO ok, too...

The 150mm is for the 27.5 wheel.
Got the 27.5 and 29 forks the same casting (lower body), equal total length from the axle to the crown?

 

[kawamaha]

You are right. The Front is not 30mm lower, its more like 15mm due to the longer casting of the 29" fork.
I still have the OEM 120mm fork of the ST, but not the 150mm OEM fork of the FSR (Cannot meassure it...)
I have also a longer shock in my ST, but mainly because I run a 27,5" Rear Wheel.
A cheap method to get the rear wheel higher is a offset shock bushing (burgtec) to compensate for the longer fork.

 

[Dirk74]

I'm not sure that its worth faffing about as in the last month I got a RS Gold 35 (150mm) for £320 and a Yari for £375 (160mm) both 29ers from Wiggle

So if you flog your Revelation for say £200 then you could be a spanking new fork for the price of the upgrades!!

I guess it is. The Yari Motion Control damper is far behind the Charger RC 2.1. The travel upgrade comes with the new AirShaft that is not expensive. Bushings and stanions are still very good, so that after replacing the internals it will be a near by new, capable fork.

 

[Dirk74]

From the data sheet of the 2021 Revelation model the fork length difference axle to crown between the 29" and 27.5" is 19mm.
Radius difference between the 29" and 27.5" wheel is 18mm.
So total 37mm difference.
Looks like that the 27.5" Levo Gen1with 150mm is more or less equal geometry as the 29" Levo Gen1 with 120mm.
I guess nobody upgraded the 27.5" to 190mm travel or did even onsider that ;-)

 

[kawamaha]

From the data sheet of the 2021 Revelation model the fork length difference axle to crown between the 29" and 27.5" is 19mm.
Radius difference between the 29" and 27.5" wheel is 18mm.
So total 37mm difference.

Yes, the front may be 37mm higher, but keep in mind that the rear is also 18mm higher (radius diff. 29" and 27,5")
And the head angles (OEM ST: 67.4° - FSR: 66.1°) show that the front of the ST is lower

btw, the head angles are from the specialized site (and make sense...)

 

[kawamaha]

Here you can see that the ST with 120mm fork is lower in the front:

rather complex subject, I know ;-)

and to answer the question of the first post, due to the length of the casting a 160mm fork will cause a flatter head angle, but a 140mm fork will provide almost the same head angle as a "normal" Levo.
I did a lot of research when I bought my Levo ST, believe it or not...

 

[Dirk74]

@kawamaha Great, thank you so much

 

[kawamaha]

just a more detailed view, where the head angle and the head tube height is pointed out...