Flip chip and headset cup changes for 29er on Moterra SL?

[KSLEX]

Hi, help me find instructions on flip chip and headset cup changes to accommodate a 29 rear wheel and less slack geo on my cannondale moterra SL

My bike's a 2026 Cannondale Moterra SL 2.

 

[Greg Watts]

Hi, help me find instructions on flip chip and headset cup changes to accommodate a 29 rear wheel and less slack geo on my cannondale moterra SL My bike's a 2026 Cannondale Moterra SL 2.

Welcome to the forum, @KSLEX. Good news: Cannondale designed the Moterra SL with exactly this conversion in mind, so you're not hacking anything together. There are two separate jobs here, and you can do them independently or together.

The Flip Chip (29er rear wheel) There's a flip chip on the seatstay that can be used to run a 29" rear wheel instead of the stock 27.5" option.

The flip chip is a 5mm hex on each side of the linkage. Both bolts are right-hand thread (worth noting as Trek have reverse thread on one side).

The critical thing to know before you start: when changing the flip chip, it's all too easy to end up chasing spacers around your workshop floor, because the flex stays cause the seatstay to spring upwards when the bolts are removed, allowing the spacers to drop.

To avoid this, hold the seatstay in place over the pivot (ideally have a friend do this or use a toe strap) while you remove the bolts and reposition the flip chips.

One Singletrack forum owner found the trick was cutting two perfectly sized pieces of dowel to hold everything in place while the bolts were pushed through.

A proper bodge, but an effective one. There are two positions for the flip chip: high and low.

The low setting with a 29" wheel offers similar geometry (just a few mm higher) to the stock setup with a 27.5" wheel in the high setting.

Interestingly, you can also run the chip in the high setting with a 29" wheel, which gives you about 10mm more BB height, and at least one Pinkbike reviewer preferred it that way. Worth experimenting.

The Headset Cups (steeper head angle) The frame is prepped to accept an Acros adjustable headset, with drop-in cups and pins that interface with notches in the headtube to set their clocking. Rotating the cups 180° gives 1.2° of head angle adjustment.

Stock ships at a very aggressive 62.5°; flipping them steepens it to 63.7°. Cannondale also offer 0° cups that put the head angle at a fixed 63.1°, which splits the difference if neither extreme suits you.

The headset change is dead simple. Just unscrew the stem and slide it up a little bit. The cups can then be taken out and rotated to the correct position.

No special tools beyond your normal hex keys. Make sure you note which way the pin notches are oriented before you pull them, so you know you've actually changed the position rather than put them back the same way.

What to expect from the combination If you're going full 29er and steeper headset, Cannondale state the flip chips will keep the geometry in the 29er configuration very close to the mullet's numbers.

The bike feels like it has a preference for a more forward weight bias in the full 29" setup, and feels slightly faster in straight lines and in chunky terrain.

Adding the steeper headset cups on top of that will quicken the steering further and put more weight on the front, which sounds like exactly what you're after if you want less slack geo.

One thing to be aware of: you'll obviously need a 29" rear wheel and a 29" rear tyre. Your stock front Maxxis DHF 29x2.5 works as a reference for the rear, though many people run something with lower rolling resistance out back.

There's decent tyre clearance even with a 29" rear wheel. Cannondale do have an official Owner's Manual Supplement for the Moterra on their website (search for "Moterra OMS" on cannondale.com) which covers the flip chip positions, though honestly the real-world tips above from people who've actually done it are more useful than the manual's diagrams. If you want, I can dig into what 29er rear wheel/tyre combos others are running on this frame.