Scalpel Si - Upgrading LEFTY 2.0 to 120-140mm Conventional Fork

[69ER]

Hi All

Need some pointers here - someone who has done this. What is a good choice for a 120-140mm conventional fork to replace my LEFTY 2.0 on my 2019 Scalpel Si? My primary motivation being better small bump compliance, more damping tunability and more travel. Don't want to sacrifice too much on weight - the LEFTY2.0 being 1600g. Looking at Fox 34 with FIT4 or Rockshox SID 120mm. Will going to 130mm or even 140mm be too much of a change of rake/trail? Understanding that these longer forks will be heavier than the 1600g of the LEFTY...any advice?

[RobertWhitehead]

So I am currently also in the process of building my 2018 Scalpel with a standard fork. My advice: go Fox instead of Rockshox. The Fox is way more plush than the RS

[dasilvarsa]

6 minutes ago, RobertWhitehead said:

So I am currently also in the process of building my 2018 Scalpel with a standard fork. My advice: go Fox instead of Rockshox. The Fox is way more plush than the RS

Agreed, But the Rockshox has better Small Bump Compliance.

[DieselnDust]

Firstly I would not fit a fork longer than 120 mm to the scalpel Si or you slack off the seat tube angle too much. I would fit a 120mm Fox 34 or RS SiD 35

a further upgrade would be a fox DPS 190x 51mm stroke rear shocks or one of the new SID luxe rear shocks of similar dimensions . This will give you 112mm or rear wheel travel.

with the conventional fork you could for a cane CFR wel angle set or works components angle reducing headset to slack the head angle off by up o 2 degrees. This will lengthen the front centre and provide a bit more stability. Try and stick with a 51mm offset fork

[69ER]

Hi Diesel&Dust

I purchased a 34 SC Fox - 120mm. Now in the process of sourcing the headset bearing kit required - and it appears to be a bit of a challenge. There is a set for this "Cannondale Reducer Headset - SI/Headshok to 1.5"-1 1/8" tapered - KP205" pictured below - but seems not sure if available in SA. I can get a conversion set that was designed for the older scalpel 29 - but that will raise the stack height by about 15mm. Can you elaborate on "cane CFR wel angle set"??

 

[Cafe Racer]

Running the new Ocho 120mm on my rig, its a beautiful thing, its not a Cannondale without a Lefty #justsaying 

[ichnusa]

You can get these reducer headsets from german online bikeshops…

Edited April 16, 2023 by ichnusa

[Mongoose!]

.

Edited May 9, 2023 by Mongoose!

[OVERDRIVE]

On 4/4/2023 at 7:09 PM, 69ER said:

Hi All

Need some pointers here - someone who has done this. What is a good choice for a 120-140mm conventional fork to replace my LEFTY 2.0 on my 2019 Scalpel Si? My primary motivation being better small bump compliance, more damping tunability and more travel. Don't want to sacrifice too much on weight - the LEFTY2.0 being 1600g. Looking at Fox 34 with FIT4 or Rockshox SID 120mm. Will going to 130mm or even 140mm be too much of a change of rake/trail? Understanding that these longer forks will be heavier than the 1600g of the LEFTY...any advice?

ROCKSHOX

[BikeisLife]

22 hours ago, 69ER said:

Hi Diesel&Dust

I purchased a 34 SC Fox - 120mm. Now in the process of sourcing the headset bearing kit required - and it appears to be a bit of a challenge. There is a set for this "Cannondale Reducer Headset - SI/Headshok to 1.5"-1 1/8" tapered - KP205" pictured below - but seems not sure if available in SA. I can get a conversion set that was designed for the older scalpel 29 - but that will raise the stack height by about 15mm. Can you elaborate on "cane CFR wel angle set"??

 

Get your local bike shop to order part number AAH4070 from Omnico. There is stock. 

[DieselnDust]

1 hour ago, BikeisLife said:

Get your local bike shop to order part number AAH4070 from Omnico. There is stock. 

^^ that’s the correct headset 

[69ER]

OK so the Project is complete - had the head-tube lower bearing pocket machined out to take a standard 52mm headset bearing. This way I could mount the FOX 34 directly into the head-tube without using the conversion kit - that would have added another 14mm in stack height. I was already lifting the head by 30mm going from the Lefty to the FOX so did not want to introduce more trail distance if I can avoid it. Doing it this way the trail is now 101mm while the stock was 80mm. On the trails this is a SUBSTANTIAL upgrade over the Lefty in just about all suspension parameters...not to mention the 220g weight saving....