AustinBike Posted March 22, 2019 Share Posted March 22, 2019 Building up my hard tail. Spec says a 68/73mm BB. Check. BB says to put one spacer on the drive side, just like on my singlespeed (same frame). but when I put the crank (SRAM) on the bike, it has a pretty big gap. Do I add extra spacers (which means the cup in the center won’t fit) or do I have to get a different crank? Quote Link to comment Share on other sites More sharing options...
Anita Handle Posted March 22, 2019 Share Posted March 22, 2019 what shell width does your hard tail have? My Dekerf is 68mm BSA. My old stumpjumper FS is 73mm BSA. Which crank interface and BB type are you using? Quote Link to comment Share on other sites More sharing options...
mack_turtle Posted March 22, 2019 Share Posted March 22, 2019 (edited) No, leave the gap. On SRAM GXP cranks, the ID of the non-drive side bearing is smaller because a ledge on the spindle hits the inside of the bearing to form a hard stop. That's why Shimano and RaceFace cranks can use the same BB but GXP is totally different. The extra space on the drive side of a GXP BB allows for a bash guard, BB mounted FD, etc. Edited March 22, 2019 by mack_turtle Quote Link to comment Share on other sites More sharing options...
AustinBike Posted March 22, 2019 Author Share Posted March 22, 2019 Here is a picture for reference: Quote Link to comment Share on other sites More sharing options...
mack_turtle Posted March 22, 2019 Share Posted March 22, 2019 Are you trying to force a SRAM 24mm spindle into a Raceface BB? The ID of the ND side bearing is too small if that's what I am seeing. Quote Link to comment Share on other sites More sharing options...
AustinBike Posted March 22, 2019 Author Share Posted March 22, 2019 That is what I was trying to get to - sounds like my crank is too big. Guessing I need a RF crank? Quote Link to comment Share on other sites More sharing options...
AntonioGG Posted March 22, 2019 Share Posted March 22, 2019 Maybe cheaper would be a GXP BB? Quote Link to comment Share on other sites More sharing options...
mack_turtle Posted March 22, 2019 Share Posted March 22, 2019 (edited) GXP bottom brackets are pretty cheap, but IME the bearings shit the bed if you get them wet AT ALL. I would ditch the SRAM cranks for an Aeffect set. I bought mine for $110 online and found chainrings for as little as $15. Edited March 22, 2019 by mack_turtle 1 Quote Link to comment Share on other sites More sharing options...
AntonioGG Posted March 22, 2019 Share Posted March 22, 2019 I had excellent GXP experience over 7 years of use and plenty of creek crossings and rainy riding (on the road). I had to replace them when they started showing a bit of play after 8k miles. Interestingly, I am shocked at the stark difference in the cheapest shimano BB vs going up a couple of steps. I had a brand new cheap Shimano BB fully lock up after RHR24 this past year (definitely gruesome conditions so I didn't take it as a big deal), then replaced it with a better one for the 12 hours of warda (equally gruesome conditions). When it came time to service my bike, I fully expected to have to replace it, but it was fine. I was told the seals are better on the higher level BBs. I'm not sure what SRAM does on their stuff. Quote Link to comment Share on other sites More sharing options...
St.Bernardo Posted March 22, 2019 Share Posted March 22, 2019 Do you have the 1mm spindle spacers for the RF cranks? My RFs have 3 small white spacers that go onto the drive side spindle. Quote Link to comment Share on other sites More sharing options...
AustinBike Posted March 22, 2019 Author Share Posted March 22, 2019 I have the spacers, if I add 2 spacers to the ND side it would probably fit. But I am thinking a GXP BB might be a more logical solution. Long term I will probably swap out the cranks but I am trying to get this bike up and running right now. $300 worth of parts are showing up today (dropper and then some) so digging out another $110 on cranks is not in the cards for me today. 1 Quote Link to comment Share on other sites More sharing options...
Kyle Posted March 23, 2019 Share Posted March 23, 2019 9 hours ago, mack_turtle said: GXP bottom brackets are pretty cheap, but IME the bearings shit the bed if you get them wet AT ALL. I would ditch the SRAM cranks for an Aeffect set. I bought mine for $110 online and found chainrings for as little as $15. I replaced so many GXP bearings on my old hardtail... I think in 2 years I replaced the whole BB once and one side individually another 2-3 times. Quote Link to comment Share on other sites More sharing options...
Txn Posted March 24, 2019 Share Posted March 24, 2019 I have a GXP BB listed in the Pay it Forward thread. You are welcome to it if you want to give it a try. I was just about to take it over to Yellow Bike because I can’t seem to give the damn thing away. It came in a box of parts, but all my cranks are Shimano. Sent from my iPhone using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
AustinBike Posted March 24, 2019 Author Share Posted March 24, 2019 Damn, Amazon is faster than you, a new one is headed here on Monday or so. I will take it anyway, but let me see whether this one that is showing up fits, good to have a backup plan. Quote Link to comment Share on other sites More sharing options...
AustinBike Posted March 24, 2019 Author Share Posted March 24, 2019 Mission accomplished, TXN had a GXP. That, with a spacer did the job. Now on to the next crisis, which looks like it might be brake related. Quote Link to comment Share on other sites More sharing options...
Txn Posted March 25, 2019 Share Posted March 25, 2019 Glad it works Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
RidingAgain Posted March 25, 2019 Share Posted March 25, 2019 (edited) Regarding the spacers... Are they suppose to fit flush with the crank spindle, or is it normal for the to be a little space? Also, I noticed on a couple of my spacers that the internal circle has some groves cut into it... Does this mean that they are for a specific type spindle/crank that has notches that line up with these groves? Edited March 25, 2019 by RidingAgain Quote Link to comment Share on other sites More sharing options...
mack_turtle Posted March 25, 2019 Share Posted March 25, 2019 On SRAM cranks, there is usually a space on the drive side where the spindle is exposed. Quote Link to comment Share on other sites More sharing options...
AustinBike Posted March 25, 2019 Author Share Posted March 25, 2019 68mm shell and 73mm BB. Should have required 2 spacers, but with 2 installed the crank would not turn. With none it was loose and shifted from side to side. With one installed it was mama bear. 1 Quote Link to comment Share on other sites More sharing options...
AntonioGG Posted March 25, 2019 Share Posted March 25, 2019 56 minutes ago, AustinBike said: 68mm shell and 73mm BB. Should have required 2 spacers, but with 2 installed the crank would not turn. With none it was loose and shifted from side to side. With one installed it was mama bear. I had to test select from all my spacers to find the thinnest ones for my last BB installation (Shimano) on my hardtail. Quote Link to comment Share on other sites More sharing options...
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