Help with frame related questions

[Bicycle Repair Man]

Washing my bike yesterday morning, in preparation for the #Space4Cycling #BigRide, I noticed this crack at the top of the RH seatstay.



I should be concerned, yes?

The bike is only about 8 months old. The frame is Reynolds 520.

Now then Furious
(You certainly should be at that)   Eight months old with a break in a place that it should never happen !!!!  Replacement frame under warranty without doubt. That is a rubbish weld that has undercut the seat tube. What I cannot see from your picture is how much seat pin is inside the seat tube. You really need the end of the pin to be well below the joints to give support to the area.
Do keep us informed about what happens when you take it back.

Cheers

Dave Yates

[bikenrrd]

A silly question: how much does a full set of lugs and cast bottom bracket weigh, for a normal diameter tubed frame and an oversize diameter tubed frame?

Thanks.

[Bicycle Repair Man]

A silly question: how much does a full set of lugs and cast bottom bracket weigh, for a normal diameter tubed frame and an oversize diameter tubed frame?

Thanks.

I have no idea !! I will attempt to weigh a set when I get a minute. The difference will be negligible.

Dave yates

[grani]

I have an audax frame that I am having a disc mount brazed onto. I am however wondering if I am better off putting the caliper on the chainstay or seat stay.

If on the CS then I can use normal rack and mudguards but with a cable run under the downtube and be restricted to 160mm discs or bigger.

If I put it on the SS then I can use 140 or 160mm discs and have a nicer cable run but will lose at least one brazed on eyelet and severely restrict the use of the other one (for a rack at least).

Of course there needs to be a brace put in if the caliper is on the SS but are there any other serious considerations?

[Bicycle Repair Man]

I have an audax frame that I am having a disc mount brazed onto. I am however wondering if I am better off putting the caliper on the chainstay or seat stay.

If on the CS then I can use normal rack and mudguards but with a cable run under the downtube and be restricted to 160mm discs or bigger.

If I put it on the SS then I can use 140 or 160mm discs and have a nicer cable run but will lose at least one brazed on eyelet and severely restrict the use of the other one (for a rack at least).

Of course there needs to be a brace put in if the caliper is on the SS but are there any other serious considerations?

Hi Grani

I would be inclined to put it on the chainstay as the seatstay mount will, as you say, foul the rack mounts. I have done this on quite a few occaisions and whilst it is a bit more of a fiddle I think it is a better solution.

Cheers

Dave Yates

[grani]

I have an audax frame that I am having a disc mount brazed onto. I am however wondering if I am better off putting the caliper on the chainstay or seat stay.

If on the CS then I can use normal rack and mudguards but with a cable run under the downtube and be restricted to 160mm discs or bigger.

If I put it on the SS then I can use 140 or 160mm discs and have a nicer cable run but will lose at least one brazed on eyelet and severely restrict the use of the other one (for a rack at least).

Of course there needs to be a brace put in if the caliper is on the SS but are there any other serious considerations?

Hi Grani

I would be inclined to put it on the chainstay as the seatstay mount will, as you say, foul the rack mounts. I have done this on quite a few occaisions and whilst it is a bit more of a fiddle I think it is a better solution.

Cheers

Dave Yates

Thank you very much for the advice it is much appreciated. I think I will try to put it on the chainstay. There is not a lot of room but it should just about fit.

I have tried to do as much research as possible and I can't find any compelling arguments for or against either in terms of structural integrity. Obviously apart from adding a brace between the chainstay and seat stay.

Do you have any experience with either failing because of a lack of strength in the tubing?

[Bicycle Repair Man]

Do you have any experience with either failing because of a lack of strength in the tubing?

I have seen seat stays break after a disc mount fitting but never a chainstay mount. A lot of seatstays are very thin walled and not suitable at all for this sort of treatment.

Cheers

Dave Yates

[Bicycle Repair Man]

A silly question: how much does a full set of lugs and cast bottom bracket weigh, for a normal diameter tubed frame and an oversize diameter tubed frame?

Thanks.

I have no idea !! I will attempt to weigh a set when I get a minute. The difference will be negligible.

Dave yates

Set of Long Shen cast lugs and BB shell for 1 1/4" DT and 1 1/8" ST and TT = 283g
Set of Long Shen ditto for1 3/8" DT ! 1/4" TT and ST = 287g

Like I said, negligible 

Dave Yates

[bikenrrd]

A silly question: how much does a full set of lugs and cast bottom bracket weigh, for a normal diameter tubed frame and an oversize diameter tubed frame?

Thanks.

I have no idea !! I will attempt to weigh a set when I get a minute. The difference will be negligible.

Dave yates

Set of Long Shen cast lugs and BB shell for 1 1/4" DT and 1 1/8" ST and TT = 283g
Set of Long Shen ditto for1 3/8" DT ! 1/4" TT and ST = 287g

Like I said, negligible 

Dave Yates

Thanks Dave.  I asked as I was trying to work out how much lighter a tig welded vs lugged frame would be.  I'm guessing 200 grams, now.

I also read somewhere that the Eddy Merckx MX Leader was heavy due to its oversize lugs.  I have a Merckx Corsa Extra, which weighs 2.1kg for the frame, so I can't see the MX Leader weighing much more than that.

All lugged steel frames in my size (550/550) seem to weight 2.1kg!

Anyway, I said it was a silly question!

[Furious]

Washing my bike yesterday morning, in preparation for the #Space4Cycling #BigRide, I noticed this crack at the top of the RH seatstay.



I should be concerned, yes?

The bike is only about 8 months old. The frame is Reynolds 520.

Now then Furious
(You certainly should be at that)   Eight months old with a break in a place that it should never happen !!!!  Replacement frame under warranty without doubt. That is a rubbish weld that has undercut the seat tube. What I cannot see from your picture is how much seat pin is inside the seat tube. You really need the end of the pin to be well below the joints to give support to the area.
Do keep us informed about what happens when you take it back.

Cheers

Dave Yates

Thanks Dave,

I don't want to say too much as I'm still waiting on a decision from the dealer on this.
(It's not too difficult to guess who the shop is.. AFAIK, they're the only Jamis dealer in the land).

The shop manager originally said they would be able to source me a replacement within a week if I could get the bike to them quickly (which of course, I did).
When I dropped the bike off, the timescale changed to 2 weeks. Then another staff member phoned me later and informed me that it could take up to 4 weeks, because they were "very busy" (what does that have to do with me?).

I will certainly elaborate further when this matter is resolved.

I checked, and the seatpost has about 20cm (almost 8") inside the seat tube.

Thanks again.

[yoav]

Other than cost, other there any advantages to TIG welding over brazing steel frames?

[LittleWheelsandBig]

Lower weight

[yoav]

Lower weight

Is that significant on a steel frame? Damn ugly though 

[LittleWheelsandBig]

Whether weight is important depends on the rider. The heat effects of TIG, brass brazing and silver brazing mean that different tubing and butting can be used.

[bikenrrd]

Lower weight

Is that significant on a steel frame? Damn ugly though 

Would you buy a hi-ten steel frame?
As above - lug less frames will save about 200 grams.  That's a 10% weight saving on a typical steel frame.  Made from something decent, of course

[yoav]

Lugless used to mean fillet brazed. Maybe still does. Looks much nicer than these welds.

Ah well, that's progress for you.

[Bicycle Repair Man]

Other than cost, other there any advantages to TIG welding over brazing steel frames?

Hi Yoav

The advantages of TIG fall mainly to the manufacturer. The process is quicker and cleaner so the tiresome process of cleaning up brazed joints is all but eliminated. With aluminium it is the only process worth considering. Weight can be saved on a steel frame against a brazed frame either lugged or fillet brazed. There is less filler rod, the butts can be shorter as less heat is involved and obviously you lose a complete set of lugs and the sockets on the BB shell. Mechanically a perfectly good way of building a frame, aesthetically not so sure IMHO.


Cheers

Dave Yates

[Euan Uzami]

Hi Dave,
In reference to this: https://yacf.co.uk/forum/index.php?topic=36893.75
At least two cases, one of which mine, where a seat post (aluminium / alloy) has seized in an 853-tubed frame.
Can you comment on the whether or not 853 tubing is particularly prone to this?

And if so can you suggest an alternative? And if so whether you do any off the peg frames made out of this that would take an OEM rohloff (i.e. with deep rear dropouts) or whether I would be looking at custom.

And can you comment on whether "dissolving the seat post with caustic soda" could have any detrimental effect on the frame?

TIA, Ben.

[Bicycle Repair Man]

Hi Dave,
In reference to this: https://yacf.co.uk/forum/index.php?topic=36893.75
At least two cases, one of which mine, where a seat post (aluminium / alloy) has seized in an 853-tubed frame.
Can you comment on the whether or not 853 tubing is particularly prone to this?

And if so can you suggest an alternative? And if so whether you do any off the peg frames made out of this that would take an OEM rohloff (i.e. with deep rear dropouts) or whether I would be looking at custom.

And can you comment on whether "dissolving the seat post with caustic soda" could have any detrimental effect on the frame?

TIA, Ben.

Hi Ben

853 is steel !! steel and aluminium in the presence of damp ideally saline "damp" will set off galvanic corrosion also known as "seized seat pin syndrome". This tube is neither better or worse in this respect in my experience, all (non stainless)steel is the same, I cant comment on any of the (so called) stainless tubes as I have little experience of them.
I dont do "off the peg" frames 
I have no experience of using caustic soda to remove seat pins but it seems to work.
What I do is if the frame is being resprayed I heat the seat tube to, I suppose about 300C, using the oxy acetylene torch, then leave it to cool for 30mins or so. Grip the seat pln in the vice along the jaws not across then using the frame as a lever get it turning and pull it out. The heat destroys the corrosion which makes extraction easy. Sometimes a spot of Plus Gas helps.
If the paint needs to be saved then I use an industrial die grinder with a tungsten carbide cutter brazed onto an extension shaft to carefully cut through the pin which allows it to collapse into the seat tube and be pulled out. I have also done this on Carbon frames. This assumes that the customer has left me enough seat pin to get a grip on. DO NOT CUT IT OFF FLUSH WITH THE SEAT LUG to "help". Several times I have had to weld an extension onto the stub of a seat pln to give me something to grip in the vice.

I have, I suppose, done several hundred, possibly thousand, jobs of this nature during the last 35 years and as far as I know with no damage to the frames. All I would say is dont try either method at home unless you know exactly what you are doing.

The best advice I can give is make sure the pin is clean when you fit it and plenty of grease or anti seize compound such as Coppaslip. Then at least once a year take it out, clean it, regrease it and replace.

Cheers

Dave Yates

[bikenrrd]

You could also use a carbon fibre seat post.

[Euan Uzami]

Hi Ben

853 is steel !! steel and aluminium in the presence of damp ideally saline "damp" will set off galvanic corrosion also known as "seized seat pin syndrome". This tube is neither better or worse in this respect in my experience, all (non stainless)steel is the same, I cant comment on any of the (so called) stainless tubes as I have little experience of them.
I dont do "off the peg" frames 
I have no experience of using caustic soda to remove seat pins but it seems to work.
What I do is if the frame is being resprayed I heat the seat tube to, I suppose about 300C, using the oxy acetylene torch, then leave it to cool for 30mins or so. Grip the seat pln in the vice along the jaws not across then using the frame as a lever get it turning and pull it out. The heat destroys the corrosion which makes extraction easy. Sometimes a spot of Plus Gas helps.
If the paint needs to be saved then I use an industrial die grinder with a tungsten carbide cutter brazed onto an extension shaft to carefully cut through the pin which allows it to collapse into the seat tube and be pulled out. I have also done this on Carbon frames. This assumes that the customer has left me enough seat pin to get a grip on. DO NOT CUT IT OFF FLUSH WITH THE SEAT LUG to "help". Several times I have had to weld an extension onto the stub of a seat pln to give me something to grip in the vice.

I have, I suppose, done several hundred, possibly thousand, jobs of this nature during the last 35 years and as far as I know with no damage to the frames. All I would say is dont try either method at home unless you know exactly what you are doing.

The best advice I can give is make sure the pin is clean when you fit it and plenty of grease or anti seize compound such as Coppaslip. Then at least once a year take it out, clean it, regrease it and replace.

Cheers

Dave Yates

Brilliant thank you Dave, sounds like you're a dab hand at it so I'll probably get in touch re bringing it round when i've next got a day off as I'm not that far from you.

I have cut it off but not flush, I've left about a centimetre to an inch to grab hold of.

[blackburnrod]

I have a 30 year old Duralinox 979 60cm frame on which the seat tube has unbonded from the bottom bracket.Is it feasible/worthwhile trying to repair or have repaired this? If so any advice on procedure or repairers?

[phillip]

its sorted now,  but......advise/comments welcome
I have a Marin Pine Mountain Mtb hardtail circa 1993/5
had no problems over the years and still had its original ch/set and BB. Been removed and refitted a few times over the years for cleaning and stuff natch
Recently decided to do a wee project and get it kitted out with disc brakes and a dyno bracket for a bit of expedition type trailer towing
Mounts fitted by R4 and his crew 
Then decided that it needed a new(er) BB and ch/set
same brand shimano deore triple with bigger rings
All went to plan until fitting the crank side BB cup, which wouldn`t 
after a bit of faffing about and wearing my thumb nail out tracing the thread start and direction of the new...and the old cups....bugger...diff er ent rotations
Never noticed before
So took a left, crank, cup out of another bike. Yep, same as new ch/set.  + they have the direction arrows on
So also took the right, ch/set cup out and tried that. Okikdoki. put the donor parts back.
got onto CRC,  very helpful,  but unheard of situation so we were both left head and things scratching
Simple solution was to buy another BB51 assy:  cheap enough at £7,
so now the Marin has 2 ch/set side BB cups fitted
BB shell is 67. summat on the vernier. didn`t bother with the summats `cos it was near enuff 68mm for me
I wiil know for future ref: but any ideas on why it is thus, who did what and why ?
Got the bike fully assembled from someone back in the mists of time in the Shipley/Otley area. Not Ellis Briggs.

[LittleWheelsandBig]

If I'm reading this correctly, the factory used a LH thread tap on both sides of the BB shell?

[phillip]

If I'm reading this correctly, the factory used a LH thread tap on both sides of the BB shell?

Crank side same as Chset side, so the answer would be yes, both lh thread