vane171

First post and having hard time using right terms (viz post title).

Bought secondhand Trek Equinox TTX 9.5 bike (2007) and my knowledge of the modern bicycle technology is somewhat limited.

While cleaning the bike and examining it closely all over, I took chain off and found the crank arms turning a bit 'stiff' in BB. In fact, I can just 'feel ball bearing balls' in BB when slowly moving the crank arms. Also when I nudge the arms, they don't continue spinning freely but stop in half turn. I have to give them quite a push to make them complete full circle before they stop.

In my experience with BB bearing adjustment on a vintage bike I owned up to now (frame from late 70s, parts from ~80s), that is too tight. I watched several YT videos how to remove and install this type of cranks but I am still not clear which nut tightening determines how tight it gets in the bearings. Is it the 8mm Allen key nut on NDS (the one that you start and finish the whole works with) which determines that (it is supposed to be torqued to some 50 Nm)?

Actually, watching on YT the installation of GXP BB which is like what I have, I don't see what (which) nut tightening determines the load which is put on bearings. Maybe because the hollow axle is conical in shape, that 8mm Allen screw pulls the whole thing together and over tightening it puts too much load on ball bearings?

And why should the 'cap be kept in place' before unscrewing that 8mm screw on NDSide as the video I was watching suggested? I have what I think is decent Allen key but likely not up to this job. I want to wait taking it apart until I get the Allen key type that mounts on socket 1/2" ratchet wrench. Plus I may have to get bigger torque wrench for re-assembly, my small 1/4" drive maxes at only 22Nm torque.

cpach

GXP effectively does not have adjustable preload. GXP is sort of a crappy design where the bearings are loaded unevenly. I think the cap you're talking about is the extraction bolt which is left in place and allows the 8mm headed bolt to self extract. You can usually use a normal 8mm wrench to remove a GXP crank-sometimes a breaker bar is helpful. Honestly you probably don't need a torque wrench to reinstall one--it's pretty darn tight, and you're very unlikely to have consequences from slightly overtorquing. Try removing the crank and see how the bearings feel--it could just be they're worn. All external bearing systems are fairly sensitive to alignment, so assuming you have a threaded BB shell you may get better performance if the shell is faced. Lastly, there's a lot more sealing on a modern BB like that, and you should not expect it to spin freely in the stand like 70s neuvo record. The seals create comparatively a lot of friction unloaded, but the loaded efficiency remains good (though, admittedly, worse for GXP than most systems). If it seems like I'm trashing GXP, I am, but I also have two bikes running GXP that are fine and I don't worry about it.

vane171

Thanks a lot for such exhaustive answer. No wonder I was scratching my head how the load on bearings is adjusted. May get better idea after I take it apart. And as you say, likely the cap is there to self extract.

At this time when shops are mostly closed, I will order M-Allen sockets online but that will take a time to come. I do have 'good' Allen keys, those with plastic/rubber handle with short side of the L sticking from the handle to side, but they don't seem to budge the screws - the one in crank arms and the other in rear deraileur which I also want to remove. This latter is quite deep in there, can't use the short side of the Allen key, so the torque I can develop is smaller than it would be otherwise.

Really reason for me going into this is I want to ship the bike to EU next time I fly and if I take off RD and even pedal cranks, that will make it all that easier to pack. I live and bike three seasons in EU and usually spend winters working here in Canada. Normally I don't use bike at all here in Toronto but I know there are some bike trails and given I am stuck here likely for the whole biking season, I will probably test them out - but the weather here tends to be mostly too hot and humid, decent days are not many and far from between. This year it looks I won't return to EU since it is locked down but eventually I will.

Videos showing removal of Ultegra RD make it look easy but when I try the same with the same wrench type like they use in video, it just won't budge even when I put some 80% of my forcing ability into it. Almost makes me afraid for the hanger. And the same for the crank arms. 'Breaker bar' is probably longer handle wrench.

All in all, examining the bike, I'd say it was serviced in a bike shop (didn't ask the previous owner about it but his setting didn't look like he worked on the bike himself). And if the bike shop is like the automotive shops I had experience with, no wonder the bolts are like welded on the bike. On car wheels, automobile shops use those pneumatic hammer wrenches and if you happen to have flat tire and want to swap the wheel for spare on the road, good luck removing the lug nuts... you really have to have good wrench and be a brute of a guy to boot.

vane171

It is threaded by the looks of it, would have posted picture but still don't have ten posts needed to be able to do that. What is that about 'facing', 'faced shell'? Is that some machining like on a lathe or what. Or is that a different type of shell?

I am not chasing performance but like the bike to be mechanically sound and tuned up, so it clicks like a watch. I am age wise beyond serious biking, never mind racing. I go for 15 to 30 mile rides, going as fast as I can keeping the heart rate up and sweating a bit, I am that kind who can't go slow for long, as probably we all are.

Right , normally on such a bike, you'd consider it a bit on the tight side and would want to back off a little before tightening the lock nut.

cpach

Any good bike shop should have a tool to face and chase the BB shell. They first run very large taps to clean up the threads, and then these taps are left in place and used to align a flat cutting tool to cut the outsides of the bottom bracket shell perfectly perpendicular to the bearings and perfectly parallel to each other ensuring bearing alignment.

cpach

Also for what it's worth bike shops overwhelmingly use hand tools, though factory assembly often uses more pneumatic and power tools. Really most things should be tightened with a torque wrench, but in practice a lot of things aren't. It's weird you're having a difficult time removing the RD, as it's really not torqued down very hard--it could have been installed with no/little grease. I actually don't like the plastic handled P wrenches for almost all things, and mostly use regular (well, extra long) L wrenches, like https://www.amazon.com/Bondhus-16099.../dp/B002YNQRXU . Like really, you basically can't do better than those. If you need more torque to remove the crank, try lining it up so that the wrench is nearly parallel to the crankarm and squeeze the two together--you can generate a lot more torque that way. It is totally possible you will need more leverage than this, but that'll work the majority of the time.

vane171

Thanks for reminding me of this technique and encouragement, it worked! The 'cap' indeed worked as a puller and it did quite some pulling for several turns. It is all nicely greased up with the light grey grease keeping the color, will leave it as is, don't need to clean and replace the grease.

Removed the seal caps and NDS bearing race (I think the inside bearing ring is called that?) doesn't move easily as it does on the DSide. Need to grip it a bit to turn it. It doesn't feel smooth inside, I mean the balls rolling, the race itself has smooth surface and covered with grease, no sign of the axle tube rubbing against the metal race if the balls would give too much resistance to rolling.

BB screwed in caps have 16 channel like groves that need special wrench to unscrew. For now, it should be ok but I should maybe get new one. I suppose you don't replace the bearing, just buy the whole thing, since it is not that expensive.

Encouraged by the success with the BB, I cupped the Allen key handle in both hands and gave it a decisive force unscrewing the RD and it finally gave way. It doesn't need to be in so tight when I put it back.

Should be much easier to pack for shipping when it comes to it. Since it is one time only, I don't mind re-assembling it on the other side of Atlantic, important is the easier, more compact packing. I look out for some hard shell bike case deal for under $100 but I think now, I might just fashion something from two plates of 1/4" plywood with some spacers to keep them apart and slip it all into a $40 soft bicycle carry bag to make it look professional. Otherwise I'd have to resell the hard shell container.

cpach

Yeah, those bbs are replaced as a unit and are pretty sanely priced. The tool is https://www.amazon.com/Park-Tool-BBT...bracket&sr=8-3, which is a pretty common shop quality tool. You can probably sub a cheaper no name tool if you only need it rarely.

vane171

While looking for new BB, I found one with telling description how the hollow conical axle 'uses the bearings'.

In my case, it is the 'Left side' bearing that has the friction in it, the DS good bearing is the one that 'floats on the spindle'.

I found cheaper wrench for the caps (16 notches, 44 mm diameter), likely will use it one time unless I pass the whole crank assembly to my old bike if the BB thread would fit.
That would motivate me twice - first, the big 53T ring (which seems to have been used heavily, even chipped on one tooth) might cost just about as much as buying the whole thing (cranks with rings mounted) and second, I'd go for 170 mm cranks (current are 172.5) if available and even better, if I could get 50/37 rings, the 53 seems a tad too steep for my riding (12/25 sprocket). Also it is quite large step between the rings but seems to be pretty common size.

Anyway, what should I look for when choosing BB? I need 68 mm and besides that, does the 'GXP' determine the rest? I found GXP logo on the rubber seals, on the caps only marking is the torque recommendation and 01-07 which I take would be January 2007 which is the year the bike was made.

cpach

Yeah, you need a GXP BB. The official SRAM ones are fine.

50/37 is not a common combo, except for 12 speed SRAM eTap (this is basically the equivalent of a 53t, because eTap uses a 10t small gear). 50/34 is basically standard for road bikes these days. The shift patterns are a little awkward with a larger gap but it shifts fine, and you get way more gear range. 52/36 is also common now but the 52t is not super useful for non-racing cyclists. Modern chainrings are designed around specific combinations and shift performance will suffer significantly if you mix and match. 50/36 exists but is rare. I'd recommend just getting a 50/34--you'll have a way better time climbing, with plenty of top end, and you'll probably get used to the shift patterns.

vane171

Sorry I mistyped, I meant 53/39. I saw this size combination a lot when looking on ebay what is being sold there. But that might be because people are getting rid of it. I gathered from some videos on YT that the days of 53 cogs are past, as are the days of 700x23 tires.
I like the tire size but 53 chainring may be a little on the steep side. The place I bought the bike from the previous owner is far and wide almost flat, no wonder the big chainring is worn while the small one is well preserved. In my case I will give that small ring fair use since I ride in rolling hills countryside and it is not far to find steep, long climbs, at least what I consider steep or long. No mountains like in TDF race for sure but enough to challenge hobby cyclists.

50/34 sounds good. Thanks for the tip. Nice you mention SRAM eTap, I was thinking or maybe just dreaming buying into it, the cheaper Force eTap, because you can just shift cassette and let it handle the front shift or other program, I think something to do with priority shifting.
Maybe as the next step, you will just set your heart rate or rpms or a combination of those and it will do all shifting for you. If you slacked off in the middle of your ride, it would detect it and change to lower difficulty level automatically or vice versa, depending how you customized it. Maybe not just a pipe dream, also not sure it wouldn't diminish the enjoyment of bike riding.

One thing about chains I wanted to ask. Apparently people take chains off bike quite frequently for maintenance and since one is not supposed to reuse those chainlinks that snap on together, I checked what is being sold and don't see those links sold in bulk, maximum couple of them, and half decent ones are fairly expensive, some even outrageously so (but I suppose those can be re-used). Are there some popular online shopping sources for these things where people buy these things? I was going to check out two or three specialized bike shops in town but now all is closed and who knows for how long yet before they open.

jgwilliams

53/39 was pretty typical for a 9-speed bike where the top gear on the cassette was typically 13 teeth. Now that we have 11-tooth cassettes the size of the chainset has similarly got smaller. SRAM AXS groupsets have gone further with a 10-tooth top gear and 46 or 48-teeth for the biggest chainring. I assume there is some adavantage to it but what it is escapes me. I suppose there's a small weight advantage?

vane171

How about this - adding ten cog allowed them to keep top gear ratio unchanged (?) with the smaller chainring and that means now you get lower gear with the same sprocket that got the ten cog added to it. It widens the gear range. I just made that up for whats it worth. If true, that would sell it to racers.

Serious hobby cyclists would buy it to get rid of cables and have clean looking bike as well as efficient shifting, less serious ones (my case) to make shifting less complicated - I rarely bother to downshift after changing to smaller chainring to compensate for big step in gear ration (but my old bike doesn't have such big difference between chainrings). Also if I did that with shift levers on downtube, I'd lose even more speed, so.

bldegle2

Here is another suggestion. I have cranks that are 5 bolt 110 bcd, both original 50/34. I ordered several 33 tooth Zephyr inner rings and ran the 50/33 with the 110 5 bolt, then shopped around and got several 48t and 46t pinned and ramped big rings, 110 5bolt, FSA. Running an 11-36 on the rear. Frankly, except for bombing real steep hills, it is hard to spin out on a 48, but on the 46 you can, next build is a single (46 or 48) to a 10-50 in the rear with the 46....for reference I am collecting SS, so my speeds are not quite the same as 20 years ago, but I can still hammer....I don't know if they make a 10 tooth for an 11 speed, it may only be the 12 speed that has the 10 presently. Someone will come out with it. With the 10 you have to be careful, some older frames may not allow it because of chain rub on the rear horizontal frame stay because of the smaller diameter 10t.. Check out Sensah on Ebay.....

Lots of hills were I live, having the gearing choices are nice. Sounds like a fun project you got going...

vane171

Shopping for BB is a headache. Amazon sellers turn out downright confusing and very few choices it seems, ordered one but the seller sent email that they will refund me as they found out they actually don't have in stock.

eBay looks like it has to be China which means some five weeks shipping and only one seller inspires confidence as far as me believing I would be buying what I need. See info in the quote below.

I have 68mm W, cups have outer diameter 44mm, inside 24/22mm (with insert to make it 22mm on NDS), crank spindle 107mm which is probably 'BSA 103mm' if measured correctly..


From the info given in the picture below (not buying from that seller), I have BSA (it even says so on the pics I just took and posted below), 68mm type of BB but I would guess the diameter would be 42mm (BB30), not 34mm (BSA). Not sure what to make of it.

But that is just guessing with the old bracket cups screwed on. I don't want to remove them until I receive the new BB (I am still waiting for the wrench anyway).


This info above in the picture is confusing but I definitely have BSA type.

wsteve464

Do a search on Amaozon for bsa gxp you should get. a lot of hits and a variety of quality.


https://www.amazon.com/s?k=bsa+gxp&i...f=nb_sb_noss_2

vane171

The bracket that comes up first on that link is the same one I already ordered on Canadian Amazon and the seller refunded me saying it is actually sold out (but it is still listed there). It would have cost me some $65 CAD.
Now on US Amazon I could buy that same bracket for $64 USD (includes import fee and exch. rate) which comes to $91 CAD, rather expensive.

I made another search and found the same product on eBay.ca for $55 CAD total, from local seller. Thanks for input that encouraged me to make this further effort. I was rather discouraged.

bldegle2

I just went on Ebay, punched in bsa gxp, lots of stuff for way less than what you are looking at on Amazon...

vane171

Well, I am buying from eBay in the end, the bracket should come tomorrow. However what you may not realize is A) many sellers won't ship to Canada and B) if they do ship, sometimes I have to pay more than just shipping cost because the goods are crossing our friendly Canadian border where they are eager to take their cut on whatever passes, in short, everything is more expensive for us in this semi socialistic protectionist country with 3/4 dollar relative to yours LOL. What you gonna do.

Cheaper brackets are pretty well all from China and that means ~5 weeks+ shipping and some sellers I have doubts regarding what they sell, probably some no-name parts, knock offs, they sell it like cookies and in all rainbow colors...