NicoBoshoff Posted November 12, 2015 Posted November 12, 2015 Ok guys, I didn't start this thread to get everyone fighting about oval chainrings...But the way I see it, it's a personal preference kind of thing. I definitely felt a difference when I went over to oval and now I wont go back.Have you gotten a solution to your problem?
raptor-22 Posted November 12, 2015 Posted November 12, 2015 Ok guys, I didn't start this thread to get everyone fighting about oval chainrings...But the way I see it, it's a personal preference kind of thing. I definitely felt a difference when I went over to oval and now I wont go back. It is a personal thing. What I discovered was that hen I went oval I felt it helped. But then I switched back to round and found I was even faster... Placibo or is oval a great training tool
raptor-22 Posted November 12, 2015 Posted November 12, 2015 Attie how much are you asking for those rings?
Attie Lourens Posted November 12, 2015 Posted November 12, 2015 Attie how much are you asking for those rings?R480.
raptor-22 Posted November 12, 2015 Posted November 12, 2015 Superb!Then for 2x cranks your rings are a no brainer. I would love to test them but sadly my XX1 chainset uses a different bolt pattern and is already chainline corrected. Any change you 94BCD 5 arm ring template AKA Race Face and Hollowgram Si 2x cranks?
Attie Lourens Posted November 12, 2015 Posted November 12, 2015 Superb!Then for 2x cranks your rings are a no brainer. I would love to test them but sadly my XX1 chainset uses a different bolt pattern and is already chainline corrected. Any change you 94BCD 5 arm ring template AKA Race Face and Hollowgram Si 2x cranks?We are working on 4 and 5 hole 94 bcd rings at the moment.
raptor-22 Posted November 13, 2015 Posted November 13, 2015 Great stuff. NIce to see locals getting in on the bicycle parts manufacturing game
Lance Roberts Posted November 15, 2015 Author Posted November 15, 2015 Ok M785 XT 2x crank. Exact same as mine. (M875 dne) So there should not be any funny offsets or anything. I will check Shimano website to see if that crank is made with different offsets. I can only think, as Myles said, that the big cog on that 11spd cassette is causing the issue 'cos its mounted further inboard than the 10spd version. With your pressfit bb you sure there are no spacers at all between bb and frame or between bb and crank arm? Howdy,I just gave my bike a huge service because I did an extremely muddy race yesterday. So I checked the press fit BB closely and it looks like there is a spacer on the drive side... Looks like about a 2mm spacer. Now let's say I do remove it, I'll then obviously have to put it on the none drive side so that I can fit the crank "axel", but will that affect anything else on the bike? I don't think I'll feel much difference in the ride because to me 2mm isn't much. Just don't want to change it if it's going to cause any other type of hassles... The one side of the BB feels quite rough after the muddy ride, so I'll have to change it any way. Could be a good time to try get the 11sp upgrade to work.
JXV Posted November 16, 2015 Posted November 16, 2015 Lance. Measure from bike centreline to centre of chainring, this is your current chainline and it should be around 50mm Yes, moving that 2mm spacer from drive to non drive side should fix your chainline issues if you can't fit spacers under the chainring.
JXV Posted November 16, 2015 Posted November 16, 2015 check this, https://www.youtube.com/watch?v=v_jows3vKsQBit of a slap in the face for those planning to buy just the 11spd cassette, shifter and RD to upgrade their 1x10 or 2x10 to 1x11. Not being able to backpedal to avoid rocks in tricky tech terrain would be a problem for me. I suggest the following checks before you spend : 1) some dedicated 1x10 frames might not be able to space the chainring far enough inwards due to chainstay interference - or you could be prevented from using larger size 1x rings2) I'm guessing most 2x10 systems should be ok because they have some clearance already for an inner chainring but after you have moved all BB spacers to the other side and fitted spacers under the spider there is little more you can do. Some frames maybe worse than others. My SC LTc is borderline..... I have one thin BB spacer left that I could move.3) still waiting to hear from the Pyga Stage owners with the new chainline offset - does this work for or against?
rock Posted November 16, 2015 Posted November 16, 2015 ja it annoyed me on a previous 1x10 set up, get to the top of the hill in the lowest gear, jump off catch your breath, jump back on and swing the pedal back to get it in the right position to keep pedaling up and the chain has fallen 'down'
WrightJnr Posted November 16, 2015 Posted November 16, 2015 On my earlier post I mentioned back pedal on the 42t cog. To be honest I have never, ever had an issue out in the field. Only on the bike stand. I just have never had the need to back pedal in that gear. In that ring you at + 8% gradient at about 5km/h. Any back pedaling will result in you falling off as you have zero momentum. Anyway, that's my view.
BrandonF_ Posted November 16, 2015 Posted November 16, 2015 On my earlier post I mentioned back pedal on the 42t cog. To be honest I have never, ever had an issue out in the field. Only on the bike stand. I just have never had the need to back pedal in that gear. In that ring you at + 8% gradient at about 5km/h. Any back pedaling will result in you falling off as you have zero momentum. Anyway, that's my view....good point. I have experienced this when cleaning my chain and wondered why the heck it keeps on jumping off the 42,...never bothers me while riding tho....#nowoman#nocry#
raptor-22 Posted November 16, 2015 Posted November 16, 2015 On my earlier post I mentioned back pedal on the 42t cog. To be honest I have never, ever had an issue out in the field. Only on the bike stand. I just have never had the need to back pedal in that gear. In that ring you at + 8% gradient at about 5km/h. Any back pedaling will result in you falling off as you have zero momentum. Anyway, that's my view. Even on my XO1 drivetrain in the 42 if I backpedal the chain will stay for two revolutions before it falls off. Its all about the angle and direction of the drive. Chains don't like being "rear wheel drive" they much prefer being "front wheel drive" . When RWD the pitch is slightly less which causes the chain to ride p on the teeth of the sprocket. Under tension the pitch is correct the chain rides deeper into the teeth at the datum line of the teeth. This keeps everything running nicely My Chainline is perfect. In the 5th sprocket the chain is deadstraight. I've played with the b-screw addjustment and this helps immensely to help keep the chain on. Set the top jockey pulley wheel teeth to around 12-16mm from the 42T sprockets pulley wheel teeth and it stays on for a couple of backward revolutions. But as Wright says, and he is right, its non issue because you are never going to be back pedalling in that gear.
NicoBoshoff Posted November 17, 2015 Posted November 17, 2015 Got my chainring and spacers from Kalbo Designs yesterday and fitted it to my 2x crank with 8.5mm cainring bolts. Massive difference in chainline. Drivetrain now dead quiet and no grinding on the chainring in the bigger cogs, which was present on the previous setup. As an aside, service from Colin at Kalbo was great. Had a hiccup with couriers which was nobody's fault, but the effort to sort everything was commendable. Will see my business again.
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