Jeffsy 29 angleset and 160mm fork

Has anyone done this? I reckon a -1 degree headset and a 160mm airshaft would keep the geometry pretty much the same as stock apart from the obvious slacker head angle and a slight reduction in reach. How do you like the change? Would you recommend it? Any downsides?

I dunno about that but I slapped a 170mm travel Fox 38 on my 2019 Jeffsy 29 and put a 210 x 55m coil shock on the back and I love it.

Little bit more front wheel lightness in steep technical climbs but absolutely ploughs on the downs. So stable.

Aren’t they integrated style headsets? I may be wrong and just basing this on my old Capra.

If they are, I’m not sure there are any anglesets available.

The Jeffsy has a zs44 top and zs56 bottom headset cup, there’s this From wolftooth and I believe cane creek have one too.

^^ Link is broken for me?

Thread revival time. I’ve decided to go ahead with this as it is fork service time anyway I figured I’d get them to swap the airshaft. I found this great geometry adjustment calculator the other day which has given me all the info I needed to make the decision (and even a little diagram of the new geo) and I’ve ended up with 160mm fork and a -1.5 degree headset from Works.

Geometry comparison:

Drawing:

It looks like I’ll be able to keep pretty much every dimension the same except for changing the head angle from 66 to 64.5, an extra 10mm travel and an extra 20mm in wheelbase. The only thing I might want to do is move from a 35mm stem to 40mm but I’ll see how it feels first.

As an aside, I got in touch with works components and they told me that they sell an EC top cup headset to fit the Jeffsy to give space for the offset bearings:

We would supply the EC44/ZS56 headset to suit the Jeffsy – the upper cup is ‘EC’ or external to allow room for the bearing to be offset, this cup will fit any 44mm headtube and just has a taller stack height when compared to the ZS44 cup – Total stack height for the upper cup including bearing cover is 18mm.

I’ve measured about 21mm between my frame and the bottom of the stem so I think I can just about fit the EC top cup.

@poopscoop sorry for the broken link to the Wolftooth version before, try this.

Oh dear…that site is going to lead to all sorts of (possibly expensive) procrastination.

Oh dear…that site is going to lead to all sorts of (possibly expensive) procrastination.

Yeah, sorry about that. It’s already cost me plenty of time and now some money.

I bought a Works -2 (EC44/ZS56, same as yours) for my bike, and it’s great. Fitting was pretty easy with a press.
Definitely made a noticeable difference (modern ish short travel trail bike, 67 to 65ish)

I bought a Works -2 (EC44/ZS56, same as yours) for my bike, and it’s great. Fitting was pretty easy with a press.
Definitely made a noticeable difference (modern ish short travel trail bike, 67 to 65ish)

How was the fitting process? I’m wondering if it’s easy to get straight as I imagine fitting it wonky would be pretty bad news.

It’s way easier than you’d think, just a little common sense and care is all you need. Some headset tools will try to rotate it though so I use the universal tool

https://www.robertdyas.co.uk/cdn-cgi/image/width=1200,quality=75/https://www.robertdyas.co.uk/media/catalog/product/cache/ee7f57371963fdaf9f4353c1acf7bd18/1/7/178061.jpg

That’s a fantastic calculator, personally I’d always just smack in the biggest change you can- it’ll change other numbers more but, really, is that all that important? Are the current numbers all perfect?

It was fine. I tied some line to the seatpost and pulled it tight then lined it up with both marks on the headset. Pressed it in with the ‘non winding’ end of the press. Had to redo the top cap once but no real bother.
Bottom was similar but flipped the bike in a stand and tied the line to the down tube in the centre.

personally I’d always just smack in the biggest change you can- it’ll change other numbers more but, really, is that all that important? Are the current numbers all perfect?

I think I could’ve gone -2 but I still need it do do “trail bike” duty so I didn’t want to go too far. Hoping this will give it more capability on the downs without changing much about the flats and the ups.

It was fine. I tied some line to the seatpost and pulled it tight then lined it up with both marks on the headset. Pressed it in with the ‘non winding’ end of the press. Had to redo the top cap once but no real bother.
Bottom was similar but flipped the bike in a stand and tied the line to the down tube in the centre.

That’s a great tip, thanks.

I use the universal tool

Also a great tip 🙂

Stick in a -2 slack set

I finally got this done yesterday.

The fork was due a service anyway so I sent it off to Sprung where it got a service, retune and travel adjustment up to 160mm. It was a great service and I’d recommend them, I booked it in on a Monday and had the fork back with me by the Saturday.

The headset pressed in straight first time without any trouble, I was careful about marking the centre of the head tube with a pencil line and then took my time over pushing it in. I did have to resort to the rubber mallet for the top cup as the offset bearing race caused my press to push it at an angle which prevented it from going in.

Riding it around the garden, the seated and standing positions feel exactly the same as before so that’s encouraging. I haven’t been out yet so we’ll see how that goes.

And here’s the final result.

Just to close the loop on this thread in case anyone stumbles on it in future.

I had a ride this morning and am very happy with the change. The bike feels unchanged for seated pedalling and climbing and subtly but definitely noticeably more capable while descending.

In summary it is exactly what I was hoping for and I’d recommend it to others 👌

Interesting.

I’ve stuck a 160mm fork on my 29er Jeffsy, handles brilliantly.

Although, you need a coil rear shock. 😉

Interesting.

I’ve stuck a 160mm fork on my 29er Jeffsy, handles brilliantly.

Although, you need a coil rear shock. 😉

I’ve spotted your photos of your bike before and it looks ace! I’ve got this tiny voice in the back of my head saying that I should get that exact same coil and it won’t go away so I suppose it’s going to happen one day!

Off topic but…
What drew you to fit a coil over the DPX air shock?

Off topic but…
What drew you to fit a coil over the DPX air shock?

The jeffsy is very progressive so suits a coil well, and it just so happened that my DPX2 had the pistons in the piggyback flip over and needed replacing by Fox under warranty, which meant I had an as new, just serviced shock which I could sell, and have a coil fitted while the shock was away.

I sold the DPX2 for £280 and the DBCoil IL was £400 with spring, so around £120 to upgrade – a no brainer IMO!

My Jeffsy is/was turning into a mini enduro machine so it suits the bike really well.

Interesting.

I’ve stuck a 160mm fork on my 29er Jeffsy, handles brilliantly.

Although, you need a coil rear shock. 😉

I’ve spotted your photos of your bike before and it looks ace! I’ve got this tiny voice in the back of my head saying that I should get that exact same coil and it won’t go away so I suppose it’s going to happen one day!

Well it didn’t take all that long. I spotted an Ohlins TTX22 on the Pinkbike buy/sell and grabbed it. It came with a 450lbs spring which I knew would be too too soft. I tried the 550lbs spring recommended by the TFTuned calculator which was too firm (~25% sag) and I’ve ended up on a 500lbs spring for ~29% sag.

After selling the DPX2, this upgrade has cost me about £150 and the difference on the bike is unreal. It’s extremely plush (obviously) but I’m also really impressed with the support and pedalling performance of the shock with a few clicks of LSC dialled in.

I took it to Bike Park Wales last week and it handled everything really nicely. The only slight complaint I could find is that I had a few harsh feeling bottom outs on larger black trail drops to flat. I switched to position 2 on the HSC dial which I think will help but I also wondered whether a progressive rate coil might improve things – either that or possibly the Ohlins 525lbs spring.

I’ll probably avoid changing the spring again for now though as I’m happy with how it rides generally, it’s only bottom out support that I’m looking for and I haven’t hit a harsh drop again since adjusting the HSC.