Moderator Cynic Posted August 13, 2021 Moderator Posted August 13, 2021 Hey. Not quite a square peg in a round hole but I need to get a 17mm spindle to bolt up into a hole designed for a 19mm thread. Is for a set of forks, they use a 19mm spindle and my dymags use a 17mm. Turning down a spindle to fit the wheel is the easy bit. What are the typical routes to sort it, some sort of helicoil, weld it and machine a new hole? Not sure what is typical.
finnerz89 Posted August 13, 2021 Posted August 13, 2021 Could you not get different bearings and a spacer for the wheel? 1
NE0 Posted August 13, 2021 Posted August 13, 2021 What would be ideal for you is a headless bushing adapter. Unfortunately I can't find one big enough!! M14 to M10 seems to the biggest. Although thinking about it 17mm to 19mm is only 2mm difference thick, so its going to be thin! which may be the reason they don't exist. The guys who could probably answer this in detail would be a custom bike maker, where everything is built practically from scratch! I'd err on the side of opening the hole even larger, welding in some solid rod and redrilling that and taping a new hole.
Moderator Cynic Posted August 13, 2021 Author Moderator Posted August 13, 2021 3 hours ago, finnerz89 said: Could you not get different bearings and a spacer for the wheel? They are ceramic bearings. A new set would cost as much as I paid for the wheels. No I'm stuck with this step. Worst case is some spacers and an oversize spindle with a nut but that is not nearly as pretty as I want it to be. I'm expecting to throw a few quid at making this work. I figure quality forks in a max is 4 figures so forking out for some engineering is expected its not a straight bolt in swap. You know what engineers are like they need to be told in infinite detail what it is you want.
Moderator Snakebite68 Posted August 13, 2021 Moderator Posted August 13, 2021 Not certain I'm going to be able to explain my idea properly, but here goes... A 2 piece spindle... Assuming one fork is threaded and the other isn't: First side slides in the threaded fork and has a thread to match up by the bolt end to engage with the threaded part of the fork. The other side of the spindle slips in as normal. The two parts thread together (don't think it will matter which is male and which is female). So, threaded side in first, tighten up, non threaded side next and screw together. The downside to this is that you will need to torque up BOTH sides separately (and how you'd work that out I don't know lol). P.S. I'm certainly NOT an engineer, and you'd DEFINATELY need an engineer to work out your torque settings. Although, getting a custom spindle made DOES give you the option to go for Titanium or Stainless Steel...
Moderator Cynic Posted August 14, 2021 Author Moderator Posted August 14, 2021 I know what you mean have seen them before. It's essentially a long nut the one I saw had an internal hex. The opposite leg could be machined for that. Making a hole bigger is far easier.
Moderator drewpy Posted August 14, 2021 Moderator Posted August 14, 2021 On 8/13/2021 at 12:30 PM, NE0 said: What would be ideal for you is a headless bushing adapter. Unfortunately I can't find one big enough!! M14 to M10 seems to the biggest. Although thinking about it 17mm to 19mm is only 2mm difference thick, so its going to be thin! which may be the reason they don't exist. The guys who could probably answer this in detail would be a custom bike maker, where everything is built practically from scratch! I'd err on the side of opening the hole even larger, welding in some solid rod and redrilling that and taping a new hole. you could drill out the threaded part on the fork larger and rethread to take whatever adapter you need. could be a tophat section so there's more clamping action on the spindle to fork leg.
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