Nubra 

Hello all,
I've been rebuilding a custom frame made for my friend Doug's dad, around 1970's.
I had the Phil Wood BB (British threaded) rebuilt by the PW shop (it is close by) and they suggested new cups, so I got them.
I disassembled and cleaned the TA Cyclotouriste triple crankset, carefully documenting how I took it apart, and then reassembling.

Now I am having a heck of a time getting the chainline to work with the triple crankset. 26-45-50 chainrings. Shimano 6 speed 11-28 freewheel.
When I removed the BB, the cups had an equal amount of threads showing on each side so I mounted the BB to do the same, (without locktight, since I was just fitting the BB)
Then mounted the driveside crank and a chain, to check the chain line.

HERE IS THE ISSUE
Small cog to small chainring , the chain brushes the middle chainring, with a noticeable deflection. This goes away when the chain is on the the second cog of the freewheel
Since PW BB are adjustable, I adjusted the cups so that the drive side cup moved out about 3.5mm. (Max is supposed to be 5mm). The chain still rubs middle chainring when on the smallest cog.

I did mount the crank to fairly close to specs, but it still needs about 5 ft/lbs torque to be correctly torqued, but I don't think it will move much further in on the spindle.

Thing is, the cranks now appear to be measurably offset from the center of the bike. The non driveside crank clears the wheel stay with about 11 mm, while the driveside crank clears teh chainstay with almost 20mm!

Any suggestions? Photos below show the "adjusted bottom bracket" with cups on the drive side protruding about 4mm from the BB case (instead of 1.5mm when centered). The non drive side cup is flush with the BB case.

IS THIS OK????
I have no idea if this is ok to do this, and don't want to locktight it till I get some feedback.

Thanks

chain is brushing the middle chainring, when on small chainring (26T) to small cog (11t)

TA crank torqued down to 20ft/lbs and bolt removed to show that there is still reveal on teh crank. Crank is not bottomed out.

Close up: TA crank torqued down to 20ft/lbs and bolt removed to show that there is still reveal on teh crank. Crank is not bottomed out.

4mm of cup when shifting BB to right to try and get chain away from middle chainring.

nlerner

Is the spindle symmetric? If not, any chance you reversed DS and NDS?

Classtime 

Small-small is gonna rub. In practice, the Granny will only be paired with the largest 2 or maybe 3 cogs.

Both of my PW BBs don't show that many threads so move the whole shebang to the NDS.

AND we would like to see the rest of this. Us Tom frame.

Nubra 

Spindle is asymetric, and I noted it during the removal. Longer side = drive side. I think you may have seen this bike in its original form on my search for help in November. Look at post in C&V, "What is my sealed bottom bracket? NOT shimano".

Nubra 

OK, I though so. Will move over and recheck just how bad that rub is on the middle chainring. You can check my original post, when I started this build on C&V under the title "What is my sealed bottom bracket? NOT shimano".
I have learned a HECK OF A LOT, on this rebuild. All my work has been on production bikes, nothing special like this. Having a BLAST!
Will post some more photos.
Thanks

dddd

I think that I am seeing thicker spacers between the bigger chainrings than between the small and middle ring(???).

This ideal spacer thickness has some proportionality to the size difference of adjacent rings, so guessing that you may have mixed up the sets of spacers(?).

I would suggest first checking that possibility out, and then perhaps moving the bottom bracket leftwards until the small ring has minimal clearance to the chainstay, (2mm max).

I always find myself taking every opportunity to shorten the spindle to reduce the "chainline" dimension (particularly with triples).
I bring in the drive side until the crankset threatens to brush the chainstay or until the front derailer can no longer downshift to the granny with authority.

JohnDThompson 

This is not unusual, especially if the frame has short chainstays and/or a large tooth count difference between inner and middle rings. The small-small gear combination is to be avoided anyway (as is large-large) as it produces the maximum chain deflection and wear.

I'd set it up with the chainline properly aligned (middle chainring in line with the middle of the rear cluster) and just avoid the small-small combination.

steelbikeguy

just in case it matters, my experience with half-step-plus-granny also shows that it is normal to rub the middle chainring if more than the first few large cogs are used.

My set-up is 26-46-49 up front, and a 7 speed 13-30 in back.



I haven't looked at the gear chart in a while, but I think that those unused gears overlap with gears available with the two large chainrings, so it isn't as if anything is being lost.

Steve in Peoria

IsleRide 

This exactly. If this is the problem then you don't have a problem. Friends don't let friends ride "cross-chain".

conspiratemus1

Contributing some myth to the discussion, I heard it said — here, I think — that the only reason manufacturers designed chainline, and chainring sizing, to avoid rubbing in small-small was that many purchasers of “10-speeds” in the 1970s just left their downtube friction shifters set that way without ever learning to use them. The manufacturers didn’t want to have to have bikes returned for rubbing noises. Customers would not believe the proposition that rubbing while cross-chained is not a defect if the shop offered it after purchase.

Whether this was actually true or not, it is true that, in the flatlands of SW Ontario, I saw many bike-boom people riding that way. Or in big-small all the time if they thought all other gears were “too easy.”

But granny-small in that nice set-up the OP has ought to rub: it’ll provide a reminder not to cross-chain, which is worse on a triple. With some gears unusable anyway, you can deduct that from chain-wrap capacity required of the derailer, and lengthen the chain to allow a larger big chainring, if you wanted. If the chain goes slack in the gears that rub, no biggie.

Nubra 

RE: I think that I am seeing thicker spacers between the bigger chainrings than between the small and middle ring(???).
I check spacers when on disassembly. They were the same.

RE: I always find myself taking every opportunity to shorten the spindle to reduce the "chainline" dimension (particularly with triples)
With modern cranks maybe, but with the TA cranks, the Q factor is very small so don't know about that suggestion. I think that would make the chainrub on the middle chainring even worse as the angle would increase as you move in.

Thanks for your attention!

Nubra 

Nice setup! Thanks Steve, I am not experience with these severe tooth drops on the chainring. Good to know.

Nubra 

Hmm, started thinking...I just assumed that the drive side spindle was the longer one. Isn't that the case with asymmetric spindles? To compensate for the wider driveside, with the chainrings? The directions fro installation from the Phi Wood shop, after they rebuilt the BB was to install the BB with the "Phil logo facing up and reading left to right for the rider". Of course this old BB no longer has the logo on it.

79pmooney

A slightly different take on cross-chaining: I used to race. I love to climb. My bikes have close to my old racing gears plus a small inner ring to make that climbing feasible without the 9,000 mile years and 25 yo body. (I still use the DT friction shifters like I raced with because they never failed me and don't impede me.)

So - I ride the hard hills on the inner ring now, but often at (relative) speed. Shift as the grade changes, both up and down. If the road goes close to flat, I stay in the inner ring and go small-small until it goes up again. Faster and less disconcerting than two double shifts. Works because I don't trim the FD to remove the rub. That rub keeps the chain from being picked up by the middle ring. Yes, yes, this is all C & V heresy. In my 9,000 mile years on two bikes, I'd kill that FD in 2 years. (Cyclone FDs were an "expendable" on my bikes.) I killed chains faster. FWs faster. It cost money. (But then, it cost far less money than buying a car and saving some of those costly bike miles!)

I still ride like this. It still costs me money. (And my best bike, a 2008 custom with 14,000 miles on it is still on its original 9-speed cogs. Granted I have about 3 cassettes of cogs and rotate a lot but that is to have a couple of wheels with different ratios and rubber going.) So - I just don't see the problem, other than it seems indexing setups could have issues with my style of riding.

79pmooney

Regarding Phil BBs (and TA) - the fit between TA and Phil may not be ideal. At least some TAs were not a common taper. But if the crakset locates well side to side with good torque, it should work just fine.

First thought - 26 to 45 is a big jump. I used 52/3-42-28 for years. Now as I age, I've gone to 50-38-24. These are 14 tooth inner to middle jumps. You have 19 tooth jump. You might consider a smaller middle ring.

Symmetry - matters only between your ears. Your legs will never notice as long as you remember to not look down. In the '70s when I raced, all road race bikes had the cranks to the right. Often missing the left chainstay by mms and a cm or more wider on the right to miss the chain. Sugino kept that well into the '80s. Maybe they still do. (For people like me whose knees appreciate low Q-factors - the distance the cranks at the pedal are apart; ie how bowlegged you ride - asymmetrical BBs are a blessing.

There is zero magic to centering the Phil Wood BB. That excess is so you can play with the location to optimize the chainlne. The folks at Phil Wood will tell you that n a second. The publish how much adjustment there is. (Chianline is described above in that nice diagram. It shows the chainlne running between the inner and outer of a double. Triple - it runs through the middle of the middle ring. Standing behind your bike, the chainlne runs between the 3rd and 4th cogs (you have a 6-speed, right? I cannot see your post as I write this). So you should see the middle ring between those cogs.

Now, if your chainline is off, several bad thing happen. Crankset too close in - more issues with ring interference like you are seeing. The chain takes a bigger beating on the small-small cross-overs. Crankset too far out - the chain takes a beating with the large-large combos (and sounds noisy to boot). In the worst scenario, the C & V police might show up at your door, take your bike(s) and haul you away to serve time over-hauling department store bikes until you scream for mercy.

Of these less than optimum scenarios, as long as you stay within a cog's width of "proper" and shift appropriately for the chainline you are riding, it's really not an issue (until you hear that dreaded knock on the door). The whole time, nobody is looking at or cares about your left crank - except! that beautiful bike will get very upset if the crank ever touches that paint. (I've honored that request on my bikes and adjusted my Phil to get 2mm clearance. Bike cringes every pedal stroke but the paint is perfect, my knees are happy and we all get along.)

So, in short - take a deep breath and relax!

Ben (who's busted more than a few of the C & V laws over the years and is still both alive and riding)

repechage

Way back Phil made 4 primary types of spindles. Unfortunately, not marked.
as I recall for a TA Triple- the overall will be 121-122mm with the double 115mm
On both there is a bias to the drive side.
I do not know is the threaded “rings” changed over time. I assume pretty similar but the latest may have a slight chamfer at the teeth as seen in your image.

that out of the way - a few things
aside from the new bearings and rings is there Anything else different?
that was unclear. A 3x5 may not have big cross chain issues besides near ratio duplication and friction. A 3x6, 3X7 - I would expect middle ring hang ups with the small/ small.
as noted chainstay length plays a part
I cannot tell the chainline now.
the chart is for a double front- a triple should have the middle ring in line with the center of the rear cog assortment.
I can note that those cranks are Near the end
of the spindle... you really don’t want any more engagement- that is my concern with spindle type - the cranks might be a bit stretched- I have seen this- my suggestion is to make sure there is still taper on the Backside of the arms visible. My hunch is the drive side arm is 1-1.5 mm too far engaged but the damage may have been done previously. I would install the arms dry- not lacquer thinner clean but not using and added grease- too much grease can cause problems- I don’t see any here, (good) just a comment for others

measure the spindle overall and offset from the drive side... super minor chance but Phil may have swapped parts? ( doubtful just thinking of all scenarios)

Nubra 

Hello Ben,
"the fit between TA and Phil may not be ideal. At least some TAs were not a common taper."
The spindle is a ISO taper, as this PW BB was made for the TA crank.

"You might consider a smaller middle ring."
This is a rebuild for an old friend, his father's bike that rode cross country twice, in the late 70s' and then early 80's. The current rings are all that remain of the collection of chain rings that his dad used to change quite frequently.

...the C & V police might show up at your door, take your bike(s) and haul you away to serve time over-hauling department store bikes until you scream for mercy."


Thanks Ben, but I actually would love to answer a knock at my door by the C&V police!!! and look forward to it.
Cheers!

Nubra 

The spindle is a ISO, which is what fits the TA crank. Spindle is 122.
PW has NOT changed the rings for this BB since origin in 1975. (they mention that in their website)
I actually spoke by phone with the machinist who did the rebuild. He was delighted to see one of these older BBs. I doubt any error was made, or switch in parts.

You are right, the cranks are near the end and are stretched. But, the cranks, on both sides, still look square in the inner side. I will encourage the owner to refrain from casually removing the cranks in the future, as they clearly are stretched, and may be getting close to loosing their grip. A mechanic pointed this out to me on a stronglight crank that I was thinking of pulling. It was from him that I learned about the "softer aluminum" on Stronglights and TA cranks.
And yes, I will install them dry (even though PW does recommend that the spindle be greased, just for the reasons you described.
Cheers and thanks for your thoughtful response.

JohnDThompson 

Perhaps this can help?

conspiratemus1

Right you are. A reason to move the chainrings inboard and accept worse rubbing in the granny would be if you wanted to bias the chainline to make it more like a double. Then the big-big crosschain would be not much worse than on a double, at the cost of being able to use only the 2 or 3 largest sprockets in granny. This could suit your riding style if the granny is used only occasionally. On the other hand, if you were going to use granny and middle most of the time and large only rarely, and then only for the small sprockets like for loaded touring in the mountains, then you could move the chainrings out farther. (If the front derailer could cope.). But it sounds fine for general-purpose riding the way it is.

repechage

that is good, but later than the original sheet.
Nubra reports a 122 mm spindle... the first Phil description sheet was typed in courier font.

JohnDThompson 

As the sheet notes, "we make other spindle lengths for special purposes or clearance problems."