- Mattias Hellöre
- in the industry
- Posts: 554
- Joined: Fri Sep 23, 2005 6:34 pm
- Location: Insjön, SWEDEN
To be honest, this derailleur is not what I bought for me as private customer, more for my company which does develop tuning stuff for anyone who wants it.
But it is light, it helps a lot.
I thought, yeah why not, so here is the start of my process turning my SRAM in 11 speeds.
Unlike monchito, instead of adapting the hub, im going to attempt to adapt the cassette, out of reasons to swapping cassettes onto other wheels, and also machining skills. So i decided to piggy back the bigger cog onto the back of a spare Red cassette i had in the garage. I found somespare cogs that were eligible for this. So im turning my 11 - 26 cassette into an 11 - 26 +2 or an 11 - 28. I started by measuring the distance between the cogs, then made sure i could use the hub with a two cross spoking (this is wider than direct pull spokes) after an "Official maybe" i went ahead with it. i figured that if i used the small spacers from a chain it would space my new cog nearly perfectly from the inside edge to the cassette. so i pulled them off my old Sram red chain.
this shows where the new cog will sit
here is it with the new cog placed on.
So i lined up the cog with the free hub splines, drew on where it was going to go so i could place it easily. I now have to drill the back of the Sram and tap it, i might also run a nut on the inside as extra precaution. Ill drill the cassette while having both cogs on a free hub to make sure its in the right spot, then i will remove the splined section of the new cog (marked by the blue circle on the above photo, and then using counter sunk bolts attach it to the outer of the cassette using the spacers from the chain.
this is the placement of the chainspacers
once attached and trued (like a wheel) ill mount it on the hub. TECHNICALLY it should fit any exisiting shimano 10speed free hub. the only for seeable issue is contact with the spokes. once i have a cassette functional and tested, (ill adjust the 10 speed lever to work on the cassette except the smallest 11T cog as it keeps standard spacing) i will mill the section from the lever internal to accomodate the new cog. Then it should be functional.
Im waiting to use the mill from my old school, as its summer holidays here. then i should be all go. Here is a 11 speed SRAM red Powerdome+1 cassette teaser photo for you all!
ENJOY, and suggestions hit me up!
I started by drilling the bolt holes to into the back of the cassette, i used a 3mm bit in the drill press, i then went fractionally bigger to 3.5mm to run a 4.0x0.5mm bolt.
I then ran the 4.0x0.5mm tap through all the holes to create the thread in the actual cassette, though i assumed the cassette wall would be to thin so i made the decision to put nuts in the cassette as extra re enforcement.
The tested my bolts would fit, and cut them to the correct length (they were a smidge to long)
Checked the layout of all 6 bolts now, made sure they were the correct distancefrom the hub to centre the new cog.
Here is a pic of the nut on the inside of the cassette to provide extra strenght under torque.
Next i set out to drill the mount holes in the new cog. this photo shows that i enlarged the holes to fit the new bolts, and i countersunk the bolt heads to keep them out of my spokes. The bolt heads dont sit completely flush but they are fairly close!
This shows the bolts sitting in their configuration, semi flush, in the right spot next step here we come!
I then tested the fit of it, i bolted it to the cassette and dropped a spare freehub into it to check alignment, it was SPOT ON! +1 for accurate measurements and machining!
The cassette bolted roughly together with all 11 speeds!
Next step was to piggy back the new cog onto the cassette by cutting the splined internals out of it. I simply ran a hacksaw through at each point of the cog...
Here is the cog finally sperated, its pretty jagged but as my first prototype it doesnt matter. My next version, on my racier 11-23 cassette will be more visually pleasing!
All bolted up! it sat on the cassette really nicely, really happy with alignment and truth of the spin. It cleared the free hub nicely too!
Mounted on the hub...
Mounted on the bike, and functioning (on the 10 speed lever as i havent started the conversion in the lever yet) Note, that is a wheel not just a hub, i had the wheel spinning so you cant reall see them. It shifts like normal (normal for a tuned to hell rear D) it doesnt move the derailleur into the spokes, i havent had an issue yet. Ill put 200km on the cassette this weekend and see if i can break it!
What i like about my design is that it should be compatible with any existing 10 speed freehub. It fit my American classic wheels, my yishun wheels, and ill start trying them on friends zipps and enves....
I will be bolting the new cog further from the hub next time as an improvement on stiffness and also room between the bolts and the spokes as this could cause issue... Ill keep you all updated any how!
I did 4.5 hours ad another 2.5 the day before on the cassette with only minor tuning issues which I fixed in the fly. It shifts really smoothly into the big gear while going up hill, and shifts back down the cassette no worries. I'm really happy with the result
The stock weight on my scale was 19g including the bolt as pictured.
After my initial round of tuning, I came out at 17g w/ the stock bolt.
Today I saw a thread where a guy had made a mount using carbon fiber. It has two clamps (one on each side of the stem). Its a prototype but it got me to thinking. His weighed in at 17g or so. Granted I think some changes could be made to the design which I mentioned (he asked for ideas) which could indeed decrease the weight. But it got me to thinking...so I went at it again this afternoon.
In the end, I slotted part of the actual band portion of the clamp and then opened up the sides (where they were previously drilled). It is not the prettiest thing out there but it still clamps down tight enough to keep it from moving and now weighs in at 16g w/ the stock bolt. I now need to put together a list of screws/bolts that I want to order form Toronto and make it happen as I am sure I could shave another gram or two by swapping out the stock bolt to an aluminum or better yet a delrin or nylon version.
I realize that I need to steady my hand a bit and work in better lighting. None the less, it was a fun little project and best yet, it still works!!! So while the guys prototype is carbon and looks pretty clean. I am thinking that something like that would retail for probably close to double what the standard Bar Fly does. With that in mind and knowing that a standard version can be tuned down to less than a sharp looking carbon one, I think I am pretty happy.
$35 for Bar Fly
$8 for Dremel tip
1.5 hours of my time to do the work (this includes breaks due to the wife/kids constantly calling me away)
DIY tuning of a stock part to be lighter than something designed to weigh less and w/ better materials....PRICELESS!
In any case, with the correct tools, I am thinking that some more material could be trimmed off from around the mount itself (around the bottom and even on the side portion where it is pretty tall (top to bottom) (you can see this area in the last picture thru the top portion I hollowed out. But I'm content for now (until I get the new bolt anyway).
Thanks for the inspiration guys.
1spd wrote:I went over it with 600 grit paper this morning and smoothed everything out as best I could. Best of all it all looks the same color now and is very smooth. I also threw it on a scale here at work that reads a little deeper than mine at home and came up with 15.7g w/ stock bolt. I'm going to be looking around some of the labs here today to see if I can track down a nylon bolt so wish me luck!
Nice work¡¡¡ If you want, you could try to sand with that 600 waterproof paper and oil (any oil) for a still smoother finish.
Good luck with the bolt
This is the idea. I´m doing the same but with the aluminium/titanium/carbon combo. Finally i reject to modify a Dura-ace Cassette. For that price i can buy the materials i need to do this and other projects.
Brilliant, man¡¡ keep pushing
What will be the next thing??
Pd: I still didn´t the drawings to explain what i mean with "negative radial", but i´ll do this week for sure.
As for new projects on the bike, i may have a crack at making some carbon cable housings... More news to come!
Here is the final lever configuration to run an extra gear.
First off you have to figure out where your cutting the barrel, its not where i first thought it would be. Basically go to the biggest gear you can, then shift the cog one more, SRAM users will know when you try shift past that allowed by the shifter you get an extraloud "clack" and the derailleur doesnt move. The barrel does though, so i over shifted and marked where the cam came down on the barrel. This is where the edge to my extra slot will be. Its hard to explain, but the lever shifts using a pair of cams against a notched / slotted barrel.
The red circular but is the bit the barrel mounts on, the notched / slotted bit it what i call the barrel, it rotates to pull the cable (which goes around the red 'Drum') and the two cams move with the lever to stop the barrel from rotating. Very clever design!
This pic demonstrates where the barrel moves to after over shifting it (trying to go to a bigger cog than your biggest) you can see just above the cam is my mark on where to start my new notch in the barrel.
This is the barrel. You can see the blue mark and small trial cut i made to see which dremel tool makes the best cut, (it was a small metal tip with a almost sandpaper tip, but all metal) This mark was checked by removing and remounting the internal mechanism on the lever about 4 times to make sure it was right.
After taking the majority of the material out of the barrel with the dremel (sorry no photo) i went to my mini files, i used a triangular file as it let me cut the face of the slot at the right angle relitive to the direction the cam arrives in (slightly inverse negitive). This took only a few minutes to smooth the cut and then clean up any issues i had.
I Had to re file it about 0.15 of a millimetre as my slot was a tiny bit far away from the rest of them, this took a few sweeps with the file and it worked perfectly!
Here it is in the 11th gear, you can see the surface between the cam and the next notch is a bit rougher than the rest of the barrel, this is before i quickly polished it so it slid smoothly, it shows that the cam actually holds the 11th gear in place though.
Here are two videos, one of the lever working 11 shifts:
And two of the Rear Derailleur functioning on the 11 Speed cassette.
So today i re assembled it all and went out for a cruisey ride with Anton Cooper (Under 19 world MTB Champ) and it perfromed really well, the shift from first to second gear is smooth and exactly like shifting on the standard barrel which means my measurements and then cutting was in the correct spot! Ill put 250km on it this weekend and report back, for now im proud to announce the second SRAM Red 11 speed in the world! Enjoy
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