Looking for 3x chainring, cranks and a square taper bottom bracket.

[i24]

My "pavement special" needs some TLC if it is going to get round CTCT again and I need some parts. It is a Hansom rigid steel frame "mountain bike" from about 1990.

It still has an original Shimano "Biopace" chainring. But it is worn and needs to be retired. I an happy to replace it with a conventional round chainring (I will keep the old one in case someone wants to restore it to original one day) but for the moment I want to ride it. The original is a combined item with chainring riveted onto the cranks. So I need a 3x (7 speed) chainring, 48, 38, 28 teeth (but wider ratios could be fun) on 170 mm crank arms, all to fit on a square taper bottom bracket.

Then I am also battling with the square taper bottom bracket. I have been through two modern cheap "cartridge" type BB's in the past few months, but these have fine threads and the non drive end is a thin walled item. It seems the threads strip or slip and come loose in the frame (the frame threads might not have very tight tolerances). I am looking for an old fashion square taper bottom bracket with cones and loose balls, 128mm long. Or can I use locktight on a threaded bottom bracket? 🤔🙄

Finally I need to get the wheels rebuilt. It has galvanised spokes which are now more rust than steel. The aluminium rims are also tired - the rim brake surfaces are worn and the front rim is a bit distorted where the aluminium hoop was joined. The hubs are decent quality and rather unique so I would like to keep them. So I need 2 off 36 hole aluminium mtb rims, spokes, brass nipples and somebody to put them together. Tubeless compatible rims might be nice, but I currently use tubes + sealant which works well for me, so I am happy for something that is closer to period original. But the wheel project can wait till after the CTCT.

Any advice where I should go shopping for the above?

Or does anybody have surplus items they want to sell?

Nothing needs to be new or modern, nor totally original, on this build. But it will get ridden regularly, so quality and reliability would be appreciated.

 

[Prince Albert Cycles]

1 hour ago, i24 said:

My "pavement special" needs some TLC if it is going to get round CTCT again and I need some parts. It is a Hansom rigid steel frame "mountain bike" from about 1990.

It still has an original Shimano "Biopace" chainring. But it is worn and needs to be retired. I an happy to replace it with a conventional round chainring (I will keep the old one in case someone wants to restore it to original one day) but for the moment I want to ride it. The original is a combined item with chainring riveted onto the cranks. So I need a 3x (7 speed) chainring, 48, 38, 28 teeth (but wider ratios could be fun) on 170 mm crank arms, all to fit on a square taper bottom bracket.

Then I am also battling with the square taper bottom bracket. I have been through two modern cheap "cartridge" type BB's in the past few months, but these have fine threads and the non drive end is a thin walled item. It seems the threads strip or slip and come loose in the frame (the frame threads might not have very tight tolerances). I am looking for an old fashion square taper bottom bracket with cones and loose balls, 128mm long. Or can I use locktight on a threaded bottom bracket? 🤔🙄

Finally I need to get the wheels rebuilt. It has galvanised spokes which are now more rust than steel. The aluminium rims are also tired - the rim brake surfaces are worn and the front rim is a bit distorted where the aluminium hoop was joined. The hubs are decent quality and rather unique so I would like to keep them. So I need 2 off 36 hole aluminium mtb rims, spokes, brass nipples and somebody to put them together. Tubeless compatible rims might be nice, but I currently use tubes + sealant which works well for me, so I am happy for something that is closer to period original. But the wheel project can wait till after the CTCT.

Any advice where I should go shopping for the above?

Or does anybody have surplus items they want to sell?

Nothing needs to be new or modern, nor totally original, on this build. But it will get ridden regularly, so quality and reliability would be appreciated.

 

If you are in CT it’s Woodstock Cycles .

[100Tours]

Much respect for the upgrade project.

On the wheels, the rebuild is only justified by wanting those hubs. You should find some cheap and very decent 26 wheel options listed for sale. Rebuild rims and new spokes will come in around R3000 (a guess), so do have a look at the classifieds.

You crank options are multitude. There are various external bearings options from Shimano or SRAM that will fit your requirements, so don't feel too tied to the old school bb. Look for a second hand triple and a pair of threaded bearing cups on a MTB standard and that should work, and also gives you a few extra options. I wouldnt go for loose bearings unless the vintage matters. Loctite on your BB has been done before..

 

 

[i24]

Some feedback. Locktite on the BB did not fix the problem, so I took the Hansom to Woodstock Cycleworks....

They ordered and supplied a new Shimano chain ring/crank set and a new BB. But it turns out that the BB was situation worse than expected. The bottom bracket housing was distorted - likely since manufacture as it is made from a seam welded tube - and the thread was stripped enough to let the BB slip. But Nils was totally committed to getting it fixed.

First attempt involved inserting a metal shim between the BB and the housing. A bit brutal but Nils reported that it has worked before. Alas it did not quite work on my Hanson, and it came loose after about 20 km. So I rode the argie on my DS MTB.

I was ready to give up on the Hanson but Nils said to bring it back. His 2nd attempt was to "panel beat" the BB housing to correct the distortion and to restore some "tapering" where the housing had stretched. After that he re-cut the BB thread. This restored enough thread to secure the BB.  Nils refused to charge for his labour for this 2nd attempt.

The BB has has since completed a few rides, including some significant climbs and it is still holding. So the Hansom will carry on rolling for a while, hopefully another decade or two 😄

With regards to Woodstock Cycles. They were totally honest and committed. Most LBS would have refused to touch this bike and rather try to sell me something that I do not want. Nils was understanding why a grey beard like myself chooses to ride a bike that could have been scrapped years ago, and went out of his way to keep it rolling. (Indeed he has a similar Hansom MTB hanging up in his shop).

Their shop looked full and pretty busy, which is great, because we need them to be around for many years!

[Hendrick Banda]

Ihave the crank and bb 0839256648

[Hendrick Banda]

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Edited September 13 by Hendrick Banda