So, up to now I have done a few upgrades to the bike through 7 years of ownership: Ergon grips, XT 4 piston brakes, 2021 Fox Factory 160mm Fork (reduced travel to 150mm), 2021 Fox Factory DPX2 and S-works seat stay and shock yolk crash replacement upgrade.
A few weeks ago, I scheduled a demo for a 2025 Stumpjumper 15 Pro, S5. I was surprised that the S5 did not feel bigger than my Stumpjumper LT. I was sold on how well the Stumpjumper 15 pedaled. I was also thinking what modifications could make my Stumpjumper LT ride like the Stumpjumper 15 aside from the geometry and genie shock.
I wanted to pull the trigger on the Stumpjumper 15 Evo Expert build, but those bikes are out of stock until mid to late August per Specialized. So, I thought it would be a cool exercise to do some modes to my Stumpjumper LT.
The Modifications:
Specialized Stumpjumper LT Link (2018-2020) | US | Cascade Components
Amazon.com : XFUSION Manic Dropper Seatpost, OD:34.9mm-100mm/ 125mm/ 150mm/ 170mm/ 190mm/ 200mm Travel, Internal Cable Routing with Remote Lever and Retail Package,for MTB and E-Bike : Sports & Outdoors (I thought that I was getting the 34.9mm dropper post, but I purchased the 30.9mm dropper by mistake, so I have to purchase a 4mm shim. I am currently using a modified piece of pvc as a shim.)
Amazon.com : Shimano Cs-M5100 Cassette 11 Speed, 11-51T : Sports & Outdoors
I currently have an XT DYNA-SYS11 derailleur paired with the M5100 cassette. I made some adjustments with high and low limit screws and the B screw, and the shifting is working. I may upgrade the derailleur though.
Era Handlebar | Era Carbon MTB Handlebar for Enduro & Trail | Race Face 40m rise 800mm width.
The bike pedals exponentially better than with the 11-45T cassette!! Small bump chatter is greatly reduced due to the added travel of the cascade link. I run the bike in the high flip chip setting as I like the pedal efficiency. The cascade link is noticeably different from the oem link. I can feel the extra 5mm that the cascade link provides. The bike does not sit high in the high flip chip setting it sits a bit lower, or with the change in progression causes the sag to be deeper?. Sitting on the Stumper Jumper LT feels similar to when I sit on my Yeti 160e, as that bike has modern geometry. What I find interesting is on the cascade website they talk about "70% more progression" and "small bump sensitivity" like what Specialized has achieved with the genie shock or Stumpjumper 15 geometry.
I am experiencing a creak from the bike from the shock area if I tighten the shock yolk pivot bolts to oem spec, which is 20nm. If i tighten them to 8/10nm the creak goes away, but the pivot bolts back out when the suspension is cycled. (Maybe some blue lock tight will resolve this?} This creak has me a bit concerned, but I do have a pivot bolt kit on order to reinstall the oem link.
The 40mm rise bars are nice. I chose not to go 50mm because I thought that would be too drastic. The front end is a bit lighter on seated climbs, but that situation is also present when the Stumperjumper LT is in the low position with the oem link and I also experienced a bit of a light front end with the Stumpjumper 15 Pro while on my demo ride.
Lastly, the 170mm dropper post is nice. I can get it out of the way more than the oem 150mm dropper.
I only have a few miles in with the new modifications, so I want to ride the Stumpjumper LT more so that I can decide if am going to keep the bike with these mods or pull the trigger and upgrade to the Stumpjumper 15 Evo.
A few weeks ago, I scheduled a demo for a 2025 Stumpjumper 15 Pro, S5. I was surprised that the S5 did not feel bigger than my Stumpjumper LT. I was sold on how well the Stumpjumper 15 pedaled. I was also thinking what modifications could make my Stumpjumper LT ride like the Stumpjumper 15 aside from the geometry and genie shock.
I wanted to pull the trigger on the Stumpjumper 15 Evo Expert build, but those bikes are out of stock until mid to late August per Specialized. So, I thought it would be a cool exercise to do some modes to my Stumpjumper LT.
The Modifications:
Specialized Stumpjumper LT Link (2018-2020) | US | Cascade Components
Amazon.com : XFUSION Manic Dropper Seatpost, OD:34.9mm-100mm/ 125mm/ 150mm/ 170mm/ 190mm/ 200mm Travel, Internal Cable Routing with Remote Lever and Retail Package,for MTB and E-Bike : Sports & Outdoors (I thought that I was getting the 34.9mm dropper post, but I purchased the 30.9mm dropper by mistake, so I have to purchase a 4mm shim. I am currently using a modified piece of pvc as a shim.)
Amazon.com : Shimano Cs-M5100 Cassette 11 Speed, 11-51T : Sports & Outdoors
I currently have an XT DYNA-SYS11 derailleur paired with the M5100 cassette. I made some adjustments with high and low limit screws and the B screw, and the shifting is working. I may upgrade the derailleur though.
Era Handlebar | Era Carbon MTB Handlebar for Enduro & Trail | Race Face 40m rise 800mm width.
The bike pedals exponentially better than with the 11-45T cassette!! Small bump chatter is greatly reduced due to the added travel of the cascade link. I run the bike in the high flip chip setting as I like the pedal efficiency. The cascade link is noticeably different from the oem link. I can feel the extra 5mm that the cascade link provides. The bike does not sit high in the high flip chip setting it sits a bit lower, or with the change in progression causes the sag to be deeper?. Sitting on the Stumper Jumper LT feels similar to when I sit on my Yeti 160e, as that bike has modern geometry. What I find interesting is on the cascade website they talk about "70% more progression" and "small bump sensitivity" like what Specialized has achieved with the genie shock or Stumpjumper 15 geometry.
I am experiencing a creak from the bike from the shock area if I tighten the shock yolk pivot bolts to oem spec, which is 20nm. If i tighten them to 8/10nm the creak goes away, but the pivot bolts back out when the suspension is cycled. (Maybe some blue lock tight will resolve this?} This creak has me a bit concerned, but I do have a pivot bolt kit on order to reinstall the oem link.
The 40mm rise bars are nice. I chose not to go 50mm because I thought that would be too drastic. The front end is a bit lighter on seated climbs, but that situation is also present when the Stumperjumper LT is in the low position with the oem link and I also experienced a bit of a light front end with the Stumpjumper 15 Pro while on my demo ride.
Lastly, the 170mm dropper post is nice. I can get it out of the way more than the oem 150mm dropper.
I only have a few miles in with the new modifications, so I want to ride the Stumpjumper LT more so that I can decide if am going to keep the bike with these mods or pull the trigger and upgrade to the Stumpjumper 15 Evo.
