RockShox 35 fork headset
- Thread starter dgc
- Start date
Thanks very much all, only problem is I will have to look for a frame or make an adapter ring for the bottom bearing, ho hum, anyway forks were cheap so at worse keep in stock.
I'm into lightweight EMTB's, but fancy a 29"er / 29"-27.5" mullet EMTB full suspension.
I'm into lightweight EMTB's, but fancy a 29"er / 29"-27.5" mullet EMTB full suspension.
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1.8 steerers are still fairly new, I'd bet there will be adapter headsets available eventually. I remember doing the same thing 10 years ago with a 1.5 steer tube and a 44mm frame headtube. There were a few options at the time, they all just moved the bottom bearing outboard of the frame. I saw the guy who made their own on that emtb forum, I can't imagine it'll take long for a headset manufacturer to see an opportunity there.
bengxe: the 1.8 steerer is a new one on me, I am a retired project engineer, I still have a 3D CAD program on my computer as I am into 3D printing etc, if I cannot find an adapter I will draw one and get it made but will have to made sure the head-stock on the frame I do have in stock has the thro" clearance to take the Rockshox fork otherwise as before I will keep the forks in stock.
The through clearance would just be a matter of adding enough stack height (to the adapter/ bottom headset cup) to get a small enough section of the steerer inside the frame. This may be a good use for a 3d printer, you could make adapters at a few different heights to see how low you can go before the steerer rubs in the frame. I'm assuming 1.8 steerers are still 1 1/8 on the small end, right? I'm also assuming you have a 44/56 headtube, that seems to be the standard.
Yes you are not wrong, I can do a 3D a model in my CAD program, export it as a STL file to Ultimaker Cura to produce a file which my Creality Ender 3 Pro 3D printer will work with, once I have the shape I can export it as a DWG / DXF file which a CNC lathe will work with. Clever what you can do with modern technology.
Looking for a ZS66 lower like this?
acros-components.com
zs66 headset lower part
Semi-integrated headset (zs) for frames with 66mm head tube at the bottom. In our zs66-headset-bottom-part, the combination of angular contact ball bearings and well thought-out sealings ensure durability with minimum maintenance and...
acros-components.com
Have had a play on the CAD system and this is what I have got so far using the 3D printer, just did a standard print, I can now do a test fit once the bottom bearing and crown race arrives. The crown race was a right pain to find without buying a full bearing set as normally it seem the 1.8" bottom is used with a 1.5" top to allow for internal cables but retaining a 1.125" steerer.
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Don't know if this will help, but Cane creek has an article on headsets, they may even make something that will fit your setup:
Everything You Need To Know About Headsets - Cane Creek
Everything You Need To Know About Headsets - Cane Creek
Well here it is, a RockShox 35 fork fitted in a Boardman MTR 8.6 frame. I am going to check the head angle which as standard is said to be 66 degrees, I was going to do a mullet job on it but 27.5" rear and 29" front might be a bit severe, will have to look at tyre options otherwise will stick to a pair of 29" wheels. I can do an offset bush job on the rear suspension and with the RockShox 35 fork I can open it up and reduce the stoke from 140mm to 130mm to offset the adapter. But before all that I must check the chain-line for the TSDZ2 mid drive now I have reversed the lower pivot pin. Aiming to build a updated version of my Boardman Team FS 650b which is fitted with 26" wheels running 2.5" tyres with a 320mm BB height.
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Checked the head angle and we are at 64 degrees with a 29" (2.3") front and 27.5" (2.5" tyre) rear combo with a 340mm BB height, I can reduce the head angle with off-set bushes in the rear shock to lift the back or drop the fork stroke by 10mm or a combo of the two. But with a 27.5" (2.5" tyre) front and rear combo the head angle comes back to 65 degrees and the BB height drops to 335mm approx. Food for thought, the BB height for a standard MTR 8.6 is 341mm, so it is a case of more investigation.
This is awesome, I hate new bike industry standards and I love big forks.
The geometry is something you'll want to figure out for yourself, but in my experience with a similar bike, the benefits of going lower outweigh other geometry changes. I would probably start with the offset bushings and lowering the fork and then run the smallest wheels I could tolerate, but ground clearance to your TSDZ2 may be an issue.
The geometry is something you'll want to figure out for yourself, but in my experience with a similar bike, the benefits of going lower outweigh other geometry changes. I would probably start with the offset bushings and lowering the fork and then run the smallest wheels I could tolerate, but ground clearance to your TSDZ2 may be an issue.
bengxe: I am with you, the bike in the attached file is my first lightweight "mini mullet" e-bike, 27.5" front wheel in 27.5" front forks and a 26" rear wheel, TSDZ2 mid-drive with the OSF firmware and a 10ah battery. Weight just under 18kgs and the ride suits me just fine, built with new parts mostly from Ebay and Aliexpress, at the build time was 0.5kgs lighter than say a Lapterre eZesty costing £7k or a Specialized Levo SL costing £8.5k, saved at least £6.5K. New old stock 26" frame given a modern slack head angle with the 27.5" front end. Anyone can do it and save money.
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Zambam: if you mean this one my Boardman Team FS 650b currently it has a 36v TSDZ2 mid-drive linked to 36v15ah Hailong battery, weight is around 20kgs, surprisingly the micro fenders do stop at the front direct spray coming up in the face and at the rear along with the "arse" protector on the saddle they also seem to stop quite a lot, otherwise I just like the look. I do have thoughts about going to 48v as the battery mount will take the 48v12ah Hailong.
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Finally got the new mullet bike built with 27.5" rear and 29" front wheels. The 48v TSDZ2 mid drive has a small 7Ah battery which will do for the moment, had fun updating the OSF but got there in the end without replacing the controller, the bike is a great ride now. Final job will be fitting the RockShox 35 forks in the next week or so, I left the stroke at 140mm so to offset the adapter may have to fit a 29" rear wheel / open the fork up and fit an extra 10mm sroke stop.
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