I am in serious need of some bicycle mechanic expertise! I have an early 90’s Trek T200 tandem that I picked up from my LBS part-way through a bottom bracket and headset rebuild job. I became uneasy about some of the inconsistencies I was getting about the needed parts and prices from the LBS.
Now I have several bags of parts and a stripped down frame sitting in my living room. I’ve sorted and cleaned the parts and I have some technical questions.
1.) There is a plastic “accordion-looking” thing that has/had rubber o-rings at both ends. It is imprinted with “TIOGA” on it. It obviously came from somewhere in the bottom brackets. Two things about this…I am only finding one in the bag of parts and it has been mangled by my LBS. What is the purpose of this part, where does it go, and why is there only one on a tandem (meaning did my LBS throw the other one away?)
2.) There are two spindles in the bag of bottom bracket parts that I received back from my LBS. One is 132mm long and other is 126mm long. Which spindle goes is which position, captain vs stoker? Maybe even more importantly, I am no bike mechanic but it is pretty obvious the one set of bearings, cups, and spindle is severely pitted with rust. Both sets of cups are Tange K1 1.37x24T. I am finding new cups sets on-line for about $20 each, but a new spindle appears to be a little tougher to find. Since I am probably going to have to replace at least one spindle, how much more difficult or is it even possible to convert the open style bottom bracket to a cartridge style system. Is the taper on the spindles pretty much universal for all square-holed Shimano crank arms or is there a whole other can of worms to consider with how various tapers mate with various crank arms? Does the eccentric cause any complexities with an open to cartridge bearing bottom bracket conversion?
Once I get through some of these issues, I’ll probably have more questions about the headset rebuild. It’s really rough and bearings are probably shot.
Thanks In Advance for Any Assistance You Can Give,
dnlpnd
The BikeForums Team
-adv-
This is an archived thread, you can find the full version of this thread, with images, links and more content here.
The eccentric isn't anything special with respect to the bottom bracket. Just screw in the BB.
I've even slapped a tapered-spindle cartridge BB in a 1980s touring bike, just fine.
I would assume that the stoker spindle is the longer one, to accommodate the width required for the chainrings and chain stays.
I was going to say that I have no idea about the accordion thing, but, wait! I do. I remember that my '80s bike's unsealed BB used one, presumably as an attempt to keep water out. You'll be throwing this away when you go to a modern cartridge BB system.
Have lots of fun with your T200! I converted my T100 to drop bars, commute on it daily, rode it 3,000 miles last year, and completed second (mile) century on it just last weekend. A good bike!
Just get used to the club folks asking questions like, "is that... steel?!?" and "you must have had that thing for a long time." (Yes to all of the above, Captain Carbon, and get used to staring at our backs on the next climb, sigh...)
-Greg "issues? no, I ain't got no issues" ;)
TandemGeek
Here's a link to the '98 Trek T200 specs: http://www.epinions.com/bike-Bicycles-All-78107-Trek_T200__1998/display_~full_specs
I seem to recall that most of the steel Trek tandem frames were produced in 1993 and it took several years to sell them so even a 98 would have had similar fitments as a '93. So, a pair of new or new old stock 68x122mm (NOS) BB-UN51, BB-UN52, BB-UN71, BB-UN72 or BB-UN73 bottom brackets ($15 - $30) should do the trick. These all use square taper / JIS spindles which is compatible with all Shimano, Sugino, Ritchey, and other Japanese or Asian-sourced square taper cranks. Campy and Race Face and a few other European boutique cranks are the only ones designed to be used with the ISO-spec spindles.
With regard to the plastic sleeve, only the rear bottom bracket on a tandem will usually have one of these. The purpose of the sleeve is to keep water and debris from getting into the bottom bracket bearing from seat or down tube and/or rear stays... all of which will usually have openings into a bicycle's bottom bracket area. The front bottom bracket on a tandem sits inside of an eccentric which protects its bearings from contaminants.
Shimano's sealed-bearing bottom brackets really don't need the sleeves and for that reason, they don't have them.
gregm
Here's a link to the '98 Trek T200 specs: http://www.epinions.com/bike-Bicycles-All-78107-Trek_T200__1998/display_~full_specs
I seem to recall that most of the steel Trek tandem frames were produced in 1993 and it took several years to sell them so even a 98 would have had similar fitments as a '93.
Ooh, interesting.
One distinct difference I see is that my ~1993ish T100 has significantly larger diameter seat posts than this epinions page shows for the 1998 model. I get 29.7mm diameter on my posts with my dial calipers, whereas these 1998 specs show 27.2mm.
I do have the large 1-1/4" threaded steerer, which is a match to the 1998 specs.
-Greg
dnlpnd
Great information guys...Thanks!
Totally makes sense on the plasitic sleeve being only on the stoker position, as the front spindle is encased in the eccentric.
To keep the chainline the same as stock, what do I need to know to search/order a direct cartridge replacement for a 132mm spindle with 1.37x24T and 126mm spindle with 1.37x24T?
My trek is a 1991 or 1992, I've submitted an email with the serial numbers to trek for year verfication and owner's manual. I see quite a few differences between mine and the link to the 1998 T200.
I would be cool if you guys could help me nail down a part number for an XT level BB with the above described dimensions.
Thanks Again,
dnlpnd
TandemGeek
I get 29.7mm diameter on my posts with my dial calipers, whereas these 1998 specs show 27.2mm.
The first production run of the frames used for the T50, T100, and T200 tandems used the larger 29.8 seat posts, taking a cue from Santana. They changed it to 27.2 in the subsequent production runs.
Old Hammer Boy
+1 to Gregrm's response. My thoughts exactly.
dnlpnd
It's getting scarier, because the shorter (126mm) spindle is not symmetrical. Meaning more of it would stick out on one side than the other.
We’ve determined that the shorter spindle goes to the captain position, but does the left or right side of the BB shell get the short end of the stick?
How is this offset (126mm) spindle going to effect the determination of what cartridge BB that I am going to need?
The stoker spindle is symmetrical, so that is a no-brainer.
gregm
I'll wager that the right side of the stoker's BB (triple chainrings) gets the longer end of the stick.
If you can get through this whole Web page, you'll be good to go, I'm sure:
http://sheldonbrown.com/bbsize.html
Don't miss the part about measuring chainline:
http://sheldonbrown.com/bbsize.html#chainline
-Greg
TandemGeek
I think you're making this a lot harder than it needs to be. Again, let me suggest that your best (lowest risk, lowest stress, perhaps even lowest cost, and most effective) course of action is to discard what you have and throw in two new cartridge bottom brackets... symetrical will do ... using the '98 specs for a 68x122mm or something "close enough", such as a 68x127: http://www.nashbar.com/profile.cfm?category=73&subcategory=1096&brand=&sku=8104&storetype=&estoreid=&pagename=
FWIW: My bet is that someone replaced the original BB's with what ever they could get from a LBS for next to nothing. It makes no sense whatsoever to have an asymetrical captain's spindle for a cross-over crankset on a stock production tande unless some funky cranks were in use. Asymetricals are usually used only for the drivetrain cranks to correct problems with chainline off-set on certain types of cranks or where there is an interference problem with the chainstay and, in almost every instance, you will have the longer end of the spindle on the drive side. For example, I have a Phil Wood +5 off-set spindle on one of my single bikes to accommodate my Specialties TA 110mm cranks.
Just my .02.
dnlpnd
More good information...Thanks!
I don't mean to belabor the point, but I want to get this right before I order and have to return parts.
So, we’ve established that the 126mm asymmetrical spindle probably goes under the captain’s position with the longer offset going on the left/sprocket side.
Leaving the symmetrical 132mm spindle to go under the stoker’s position.
I totally understand that the timing chains on the left side of the bike should be in alignment, which if I put the 5mm longer end of the 126mm spindle to the left side everything should line up.
Knowing the original owner and seeing the undisturbed condition of the bottom brackets, I can say with almost 100% certainty that the spindles are original equipment.
I agree that the 68x127 cartridge bearing would probably work in both positions (provided the 127mm would give enough clearance vs the 132mm original), but I feel like we are still missing something. There must be a reason Trek chose to put a 5mm offset spindle in the captain’s position. Would Trek have gone with a shorter spindle on the eccentric /non-sprocket side for some reason? Does this somehow correct any offset issues caused by the eccentric? Just a guess.
I take it from a previous reply that offset bottom brackets are available. How about a 132mm length BB? If both of these things were available this would be a direct replacement and I would not have to try substitutes.
Added: I remeasured these spindles one is 125mm w/5mm offset and one is 130mm symmetrical. I see these are both available from Phil Woods for $119 each. Ouch!
We’ve made tremendous progress here so far, but I really would like to figure out this last point. If nothing else just to satisfy my curiosity.
Thanks Again,
dnlpnd
gregm
Think "Shimano" and "Twenty bucks apiece."
Well, don't let me stop you from buying Phil products, as they're awesome, but you can just walk into an REI or an LBS and get decent-grade Shimano BBs for cheap. With the cost of the Phil parts you quoted, you'd probably be spending well more than a quarter of the bike's resale value.
If you want to be cautions, buy just one $20 Shimano BB, intending to use it for the captain's spot, but first try it out in the stoker's position to ensure that the rings are spaced appropriately far/near from the frame and make a good chainline.
Note that while it's nice to have things lined up, that timing chain is looong, and a wee bit of l/r relative offset here is way way less than you'll have all the time on the right side when you're selecting various rear cogs. I've swapped different captain cranks with different left side timing ring offsets and different width captain BBs, and the timing chain doesn't care one bit.
You could make an academic study of the whole situation and do research on Trek's historical part choices, but I'm assuming that you want to ride the bike... pretend that you got the bike with no BBs at all, and see what is available to you, and what dimensions are required to make it all work reasonably. :)
Good luck! :beer:
-Greg
zonatandem
Trek did a bit of weird stuff when they first got into the tandem market.
Wheels were also a problem with constant spoke breakage as they insisted on using 'in-house' rims, etc.
They finally got their act together after a while.
Remember at one of the early Interbike shows talking with some of their engineers and they were asking us what components we used on our custom tandem. Exchange of info is always good.
TandemGeek
I don't mean to belabor the point, but I want to get this right before I order and have to return parts.
As Rudy notes, Trek did some weird things with its tandems so I'll agree to the stipulation that the 125/-5 asymetrical front BB spindle & 130mm rear spindle are the OEM parts. I've seen very few very old Treks that still have their original bottom brackets and probably wouldn't have noticed the difference unless I'd torn one down.
The rationale is probably something like this... Given they used 140mm rear spacing, the goal was probably to get the best chain line possible and the 130mm rear spindle provided what they were looking for. In looking at what they ended up with, someone probably decided that a super-wide rear spindle and resulting tread distance between the cranks (aka, Q-factor) wasn't a bad thing given that most stokers were women. However, in looking at the front the folks at Trek decided to do what they could to narrow the tread a bit given that most captains would be male cyclists who would find a super-wide tread distance like 130mm odd-feeling at best and opted to use the -5 offset 125mm spindle as a "compromise".
Obviously, Trek subsequently looked around at the other tandems being produced and eventually figured out they had over-engineed the system. They then fell into line with just about every other tandem producer and began using more narrow and symetrical bottom brackets, as evidenced by the '98 specs, and just lived with the slightly suboptimal chainline. Santana, which uses 160mm rear drop-out spacing, has had to integrate a little adapter to move the front derailleurs out further from the frame and uses very wide bottom brackets to tweak its chainline.
For a point of reference: Our road tandems have 145mm rear spacing and we use very narrow 108mm bottom bracket spindles with what are fairly narrow cranks to no ill effect. The widest bottom brackets we've used on this tandem were 113mm.
BTW, you'll need to read the fine print on the Phil Woods. $119 only gets you the center cartridge. You'll also need to shell out $35 for the cups and $14 for at least one (they recommend two) of their proprietary splined BB cup installation tools. So, for a tandem you'd be looking at $350 shipped to your door.
When you get to the 1.25" quill headset you'll find that replacement parts can be found, but with very little variety.
gregm
When you get to the 1.25" quill headset you'll find that replacement parts can be found, but with very little variety.
The pictured item doesn't represent the 1.25" steerer model -- the one you'd use on the Trek has no step, being 1.125" diamater along its whole length.
-Greg
George Handy
I've got the Nitto stem converter on our '99 Trek and it works great. I think it looks better that a quill stem.
TandemGeek
Nitto will set you free:
I was actually thinking more in terms of threaded headsets... It's not that they're unavailable, you just need to hit up shops like Harris Cyclery or Mt Airy who will usually have the older or less common NOS components.
dnlpnd
Once again you guys have out done yourselves with great advice and information!
Great points about the Phil Woods, I knew about the special tool, but did not know about the cups. $350 is not really an option.
So, its either go back with cups ($20 ea) and new spindles from Harris ($15 ea) or trial and error the longest (127mm) sealed Shimano on stoker position ($18 ea). I don't forsee the timing chaining caring about bringing both spindles in a full 5mm on the left side, but I wonder how bad I'll be screwing up the chainline by bringing in the drive side in a full 5mm (assuming that the inner chainring clears the frame. I had our gauge technician at work take some high precision measurement on the OEM spindles. So, what it comes down to 5mm closer in on the drive/triple crank side.
Am I going to run into exotic bearing problems when I get to replacing the rusty headset bearings for and oversized head tube or does a 1.25" dia quill take a standard headset bearing?
B.T.W. Trek could not match my serial numbers to my bike. All they could say was it is a mid-nineties model and they said the geometry is the same as a T100, which they sent me a copy. I find this hard to believe.
I asked Sheldon Brown for help on this BB issue, all he sent me in his reply were links to his website.
I asked Peter White for help on this BB issue, he sent back a two line message saying that new spindles in these sizes would be nearly impossible to find. Meaning, I can waste time searching or simply install new Phil sealed BB's.