Author Topic: Help with frame related questions  (Read 149026 times)

Help with frame related questions
« on: June 24, 2011, 12:05:38 pm »
Now then people.

Some of you may have seen the thread on disc brakes for road bikes where Mr Clarion said

"Now you're here, it would be interesting to hear your views on a number of different issues.  Hope you have time to hang around and give us the benefit of your experience"

So here I am  ;)  I am quite happy to answer questions on frame related topics however I dont do personal problems, the meaning of life, what colour shorts should I buy, or is the moon really made of green cheese  ;D

Hope I can be of some assistance

Dave Yates



It's not just hitting it with a hammer but knowing where to hit it and how hard

clarion

  • Tyke
Re: Help with frame related questions
« Reply #1 on: June 24, 2011, 12:11:13 pm »
...I dont do personal problems, the meaning of life, what colour shorts should I buy, or is the moon really made of green cheese ...

Oh. :(

*run out of questions*  ;D
Getting there...

Re: Help with frame related questions
« Reply #2 on: June 24, 2011, 12:12:58 pm »
Afternoon, Mr Y. Might I mention in passing that commas in www addresses don't work.

Also - just curious: does anyone buy bespoke tt frames nowadays, or is it all Taiwanese carbon-fibre?

clarion

  • Tyke
Re: Help with frame related questions
« Reply #3 on: June 24, 2011, 12:25:57 pm »
Actually, I do have a question.

I want to use a hub gear on my tourer (531ST).  It currently has vertical dropouts.  I know I could go with a chain tensioner, but I think they're ugly, and, besides, I want to have the option of a fixed.

Now, next refurb I see the options as these:

Change the dropouts for trad horizontal ones, but I think they're getting rarer.

Change the dropouts for Rohloff-style sliding dropouts (better if I add a disc brake, of which more another time)

leave the dropouts and swap the BB (thread getting tired anyway) for an EBB, which makes disc brakes a good option (of which more later, as I say).

I've spoken to another framebuilder, who doesn't like EBBs because they change the effective seat angle, but I wouldn't have thought that was particularly critical on a tourer, though I don't have the experience to be certain (just been riding a bike for thirty years).

I'd appreciate your views.
Getting there...

dasmoth

  • Techno-optimist
Re: Help with frame related questions
« Reply #4 on: June 24, 2011, 12:29:56 pm »
I've spoken to another framebuilder, who doesn't like EBBs because they change the effective seat angle, but I wouldn't have thought that was particularly critical on a tourer, though I don't have the experience to be certain (just been riding a bike for thirty years).

I though you'd done some tandem miles?  Doesn't that have an EBB?

(They've certainly never bothered me, and seem like a much neater engineering solution that most of the alternatives -- I have a suspicion I'm relatively non-fussy about riding position, though, so maybe it matters more to others).
Half term's when the traffic becomes mysteriously less bad for a week.

Re: Help with frame related questions
« Reply #5 on: June 24, 2011, 01:03:25 pm »
Afternoon, Mr Y. Might I mention in passing that commas in www addresses don't work.

Also - just curious: does anyone buy bespoke tt frames nowadays, or is it all Taiwanese carbon-fibre?

Afternoon Ian

First one, finger trouble,  :-[ now rectified, Ta

Second one, I havent made a TT frame for at least 7 or 8 years so if anyone is buying them they dont come to me. I am totally out of touch with the racing world now I tend to make mainly tourers, audax, and MTBs so I havent a clue what people are riding.

Cheers

Dave Yates
It's not just hitting it with a hammer but knowing where to hit it and how hard

Re: Help with frame related questions
« Reply #6 on: June 24, 2011, 01:17:50 pm »
Actually, I do have a question.

I want to use a hub gear on my tourer (531ST).  It currently has vertical dropouts.  I know I could go with a chain tensioner, but I think they're ugly, and, besides, I want to have the option of a fixed.

Now, next refurb I see the options as these:

Change the dropouts for trad horizontal ones, but I think they're getting rarer.

Easiest and cheapest option. Not a problem as I probably have the worlds remaining supply of these  ;D Well, I have quite a lot.

Change the dropouts for Rohloff-style sliding dropouts (better if I add a disc brake, of which more another time)

Possible but rather more expensive

leave the dropouts and swap the BB (thread getting tired anyway) for an EBB, which makes disc brakes a good option (of which more later, as I say).

Major work required , expensive (very). If the frame is quite old, and it will be if made of 531 then personally I would not be keen on this option as you never know what you are going to find when you start dismantling

I've spoken to another framebuilder, who doesn't like EBBs because they change the effective seat angle, but I wouldn't have thought that was particularly critical on a tourer, though I don't have the experience to be certain (just been riding a bike for thirty years). Thirty years  :o Did you stop for a rest?

Yes the efective seat angle could change slightly depending on the position of the eccentric but as you say not particularly critical.

I'd appreciate your views.

Cheers

Dave Yates
It's not just hitting it with a hammer but knowing where to hit it and how hard

clarion

  • Tyke
Re: Help with frame related questions
« Reply #7 on: June 24, 2011, 01:57:20 pm »
Thanks, Dave.  Does it change the balance of options if I need to replace the BB shell anyway?  This might be the case, as I've had problems with slipping cups and worn thread.  Temporarily seems to be solved, but I don't know about the long run.

Bike is from 1996, btw.  Has done a lot of miles, and I want it to do a lot more ;)
Getting there...

Re: Help with frame related questions
« Reply #8 on: June 24, 2011, 03:47:41 pm »
Have you ever been interviewed about your approach to bike fitting? I'd be interested to read about it.

Re: Help with frame related questions
« Reply #9 on: June 24, 2011, 06:30:58 pm »
Have you ever been interviewed about your approach to bike fitting? I'd be interested to read about it.

Short answer to that is No !!!  Best I can do is direct you to our website where there is an article I wrote for Arrive some years ago at
http://www.daveyatescycles.co.uk/custom_bike_frames-Frame_Design_Considerations-38.php
I think the best description of my approach is "subjective seat of the pants" however it works for me!!

cheers

Dave Yates
It's not just hitting it with a hammer but knowing where to hit it and how hard

Zipperhead

  • The cyclist formerly known as Big Helga
Re: Help with frame related questions
« Reply #10 on: June 24, 2011, 09:44:31 pm »
Oooh, I have a question.

I recently took the bottom bracket out of one of my bikes, a campag cartridge unit, and there was some fine rust on the outside, which much have come from the frame.

As the frame is a very nice 753 Bob Jackson I would like to stop it rusting away.  What would you recommend?

Ta.

Graham
Our son does know who Boz Scaggs is, we've done ok as parents.

mikeluke

Re: Help with frame related questions
« Reply #11 on: June 24, 2011, 10:02:56 pm »
I think the best description of my approach is "subjective seat of the pants" however it works for me!!

Certainly worked for me. Never cycled seriously before and already enjoyed 2600km on a new Dave Yates fast tourer since March. Comfortable and fast. Thanks :)

Re: Help with frame related questions
« Reply #12 on: June 25, 2011, 05:28:35 pm »
Thanks, Dave.  Does it change the balance of options if I need to replace the BB shell anyway?  This might be the case, as I've had problems with slipping cups and worn thread.  Temporarily seems to be solved, but I don't know about the long run.

Bike is from 1996, btw.  Has done a lot of miles, and I want it to do a lot more ;)

Changing a BB shell is quite a serious job  involving two heatings of the tube end. I normally remove a shell by disecting it and taking the remnants off the tube ends a piece at a time to reduce the amount of heat required. If the frame is in good condition then usually this should not cause a problem, however there is an element of risk involved.
Replacing a standard lug type BB shell with an eccentric shell is an order of magnitude more complex in that the eccentric shell has no pipes for the tubes to slot into so each of the four tubes attatched to it has to be cut dead length with a perfect mitre to fit the curve of the shell. This is hard enough to do with individual tube during the build process but trying to do it with a complete frame is an absolute nightmare. I have done it a couple of times so I speak from experience. !!!
For a dodgy thread there is another fix that the purists throw their hands up and run for cover at! This is the cut and weld where a cut is made across the shell with a double hacksaw blade and then vee'd out with an angle grinder. I then TIG weld it from the centre outwards which shrinks the shell enough to cut a new thread. It could be classed as a bodge but it works and is far kinder to the frame. I have succesfully done hundreds of these over the last 30 years and had very few problems.

I think that for this frame, best bet is to sort the shell out by either method then go the sliding dropout route to give you the option of a disc if you want.

Cheers

Dave Yates
It's not just hitting it with a hammer but knowing where to hit it and how hard

Re: Help with frame related questions
« Reply #13 on: June 25, 2011, 05:31:57 pm »
Oooh, I have a question.

I recently took the bottom bracket out of one of my bikes, a campag cartridge unit, and there was some fine rust on the outside, which much have come from the frame.

As the frame is a very nice 753 Bob Jackson I would like to stop it rusting away.  What would you recommend?

Ta.

Graham

Graham

Get yourself some Waxoyl from a car accessory shop and spray the  inside of the four tubes that join the BB shell. Excellent stuff, will stop any rust dead in its tracks.

Cheers

Dave Yates
It's not just hitting it with a hammer but knowing where to hit it and how hard

Re: Help with frame related questions
« Reply #14 on: June 25, 2011, 07:52:07 pm »
Steel frames without bottle cage fixings: Is it a really stupid idea to drill and fit riv-nuts for these fixings? Are cracks likely to propagate from these holes and would thicker plain gage tube make any difference in avoiding such a risk rather than the light gage stuff?

Thanks,
Jerry

Re: Help with frame related questions
« Reply #15 on: June 25, 2011, 11:25:42 pm »
Steel frames without bottle cage fixings: Is it a really stupid idea to drill and fit riv-nuts for these fixings? Are cracks likely to propagate from these holes and would thicker plain gage tube make any difference in avoiding such a risk rather than the light gage stuff?

Thanks,
Jerry

Jerry

There have been several well known manufacturers use this system on steel frames in the past. I have never seen a frame break as a result. As long as the hole is drilled accurately and any raggy edges smoothed before the rivnut is fitted it should work ok. Rivnuts work best for this purpose on ally frames, the softer material allows the rivnut to grip the edges of the hole more securely. I would coat the rivnut with Araldite or similar slow setting epoxy adhesive as a belt and braces solution. Centre punch the hole centres and drill in stages ie 3mm, 5mm, then recommended size for your particular rivnut.
I would not do this on any of the more exotic very thin tubes but anything from about 0.6mm on the unbutted setion should be ok.

Cheers

Dave Yates

Cheers
It's not just hitting it with a hammer but knowing where to hit it and how hard

Zipperhead

  • The cyclist formerly known as Big Helga
Re: Help with frame related questions
« Reply #16 on: June 25, 2011, 11:29:43 pm »
Graham

Get yourself some Waxoyl from a car accessory shop and spray the  inside of the four tubes that join the BB shell. Excellent stuff, will stop any rust dead in its tracks.

Cheers

Dave Yates

Thanks Dave, I'll pick some up during the week and do it next Saturday.
Our son does know who Boz Scaggs is, we've done ok as parents.

border-rider

Re: Help with frame related questions
« Reply #17 on: June 25, 2011, 11:32:42 pm »
worth doing if you have Pompino.  They rust like buggery from the inside.  I did mine and the one I sold to Mr Endon, and had a load of Waxoyl left.  I got my Waxoyl on t'internet, with an applicator.  Enough for 5 or 6 frames I'd think so maybe worth sharing with other forrummers

Zipperhead

  • The cyclist formerly known as Big Helga
Re: Help with frame related questions
« Reply #18 on: June 26, 2011, 12:16:30 am »
worth doing if you have Pompino.  They rust like buggery from the inside.  I did mine and the one I sold to Mr Endon, and had a load of Waxoyl left.  I got my Waxoyl on t'internet, with an applicator.  Enough for 5 or 6 frames I'd think so maybe worth sharing with other forrummers

As I have a new Pomp, I could give it a blast as well, also my trike. The bottom bracket needs adjusting anyway, so it won't be much extra work to strip it and spray it.
Our son does know who Boz Scaggs is, we've done ok as parents.

Re: Help with frame related questions
« Reply #19 on: June 26, 2011, 01:18:13 am »
Steel frames without bottle cage fixings: Is it a really stupid idea to drill and fit riv-nuts for these fixings? Are cracks likely to propagate from these holes and would thicker plain gage tube make any difference in avoiding such a risk rather than the light gage stuff?

Thanks,
Jerry

Jerry

There have been several well known manufacturers use this system on steel frames in the past. I have never seen a frame break as a result. As long as the hole is drilled accurately and any raggy edges smoothed before the rivnut is fitted it should work ok. Rivnuts work best for this purpose on ally frames, the softer material allows the rivnut to grip the edges of the hole more securely. I would coat the rivnut with Araldite or similar slow setting epoxy adhesive as a belt and braces solution. Centre punch the hole centres and drill in stages ie 3mm, 5mm, then recommended size for your particular rivnut.
I would not do this on any of the more exotic very thin tubes but anything from about 0.6mm on the unbutted setion should be ok.

Cheers

Dave Yates

Cheers
Thanks for that very useful advice.

[edited to cut some late night drunken exuberance ::-)]

Re: Help with frame related questions
« Reply #20 on: June 26, 2011, 11:22:27 am »
Dave, what are your thoughts on fillet brazing vs lugged joints?  Is it just a case of extra work and skill to create something cosmetically better or are there structural and "ride feel" advantages to either? 

Great to see you in here by the way! (At least one of us knows what they're talking about now..)

Re: Help with frame related questions
« Reply #21 on: June 26, 2011, 11:36:07 pm »
Dave, what are your thoughts on fillet brazing vs lugged joints?  Is it just a case of extra work and skill to create something cosmetically better or are there structural and "ride feel" advantages to either? 

Great to see you in here by the way! (At least one of us knows what they're talking about now..)

Now then Mr Tewdric,

In my humble opinion, structurally there aint a lot to choose. If you build two frames of identical dimensions and tubes, one lugged and one fillet brazed. Built them up with identical components I doubt you would feel any difference in the ride. (I have had both and although the frames were not identical they were close and I did not notice any real difference). This assumes of course that the mitres were cut accurately in both cases. The strength of any joint on a frame is entirely dependant on the fit of the mitre and the penetration of the brass/silver into the joint to stick one tube onto the other right around the circumference of the tube A common beginners mistake with a lugged joint is to simply braze the tubes to the lug with no penetration through to where the tubes touch. Likewise I have seen badly executed fillets where the brass just bridges the joint with no penetration, result, broken joint !!!
The advantage of fillet brazing is that the design is not constrained by the lugs so sloping top tubes, odd angles etc are not a problem. Some people go for fillets on aesthetic grounds but the greater proportion that I see are to have a sloping TT. The down side of fillets is the extra time taken to finish to an acceptable standard which obviously puts the price up.
So basically you pays yer money etc

Cheers

Dave Yates
It's not just hitting it with a hammer but knowing where to hit it and how hard

Re: Help with frame related questions
« Reply #22 on: June 27, 2011, 12:29:16 pm »
Going back to time trial frames. The fashion currently is for tightest clearance, aerodynamic tubes, and as near to 'faired-in' as the regs will allow. By contrast a well-known rider has broken several records on this machine. It doesn't tick many of the usual boxes.

Re: Help with frame related questions
« Reply #23 on: June 27, 2011, 08:37:32 pm »
Going back to time trial frames. The fashion currently is for tightest clearance, aerodynamic tubes, and as near to 'faired-in' as the regs will allow. By contrast a well-known rider has broken several records on this machine. It doesn't tick many of the usual boxes.

Which just goes to substantiate my contention that an aero frame might save you a bit of petrol if it is on top of the car going to a race but in practice does precious little else other than suggest to  the rider he/she will go faster. !!
When I were a lad, before disc and composite wheels, aero frames, tri bars, skin suits and all the other "go faster" bits of kit, comp record at 25 miles of a time of 52.28 was held by  Dave Dungworth on a bike that by todays standards would be a touring bike !! In the early 80s my ex business partner Joe Waugh did a stupidly fast 25 of 50 mins and some seconds, cant remember exactly, on his standard 753 road bike with just a skin suit as an aid to speed. At the time this was the third fastest ever 25.
Its not about the bike, its all about the power unit.

Dave Yates
It's not just hitting it with a hammer but knowing where to hit it and how hard

Biggsy

  • A bodge too far
  • Twit @iceblinker
    • My stuff on eBay
Re: Help with frame related questions
« Reply #24 on: July 03, 2011, 10:38:43 am »
[Moderator's note: I am thinking of Stickifying this topic.  Meanwhile, this is a bump to get it back on page 1]

EDIT:   Now Stickified.
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