Author Topic: Help with frame related questions  (Read 290210 times)

Re: Help with frame related questions
« Reply #425 on: 28 December, 2016, 06:45:37 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

Does the Pompino rust from the inside any more than other similar frames?
On-One say "Our tubing (DN6) comes from a company called Founderland in Taichung, Taiwan. Off the same lines, the same material, the same dies, everything, Reynolds have Founderland put the same tubing into boxes with "Reynolds 520" on it." So surely any bike similarly tubed would rust as badly?

Dave_C

  • Trying to get rid of my belly... and failing!
Re: Help with frame related questions
« Reply #426 on: 02 January, 2017, 05:43:09 pm »
My turn to ask a question, if I may. I have bought a s/h Cotic Bfe frame and plan to move everything over from my Spec Rockhopper to the Cotic. They are both straight headtube so hopefully no problems there. It needs a new headset, so I may see if I can stretch to a Hope as I'll never really need to fit another in my lifetime.

But the frame brake line guides look like they are for cable and I have hydraulic brakes. Any suggestions? I don't want to butcher the guides but there are slotted guides for tie wraps so this may be a possibility.

Anything else I should be aware of? I have a circa 2010 Rockhopper as a donor which has 9 speed Deore crank which should fit but I have been told that unlike road bikes the crank may need shims or spacers to make the crank fit the bb? Can anyone elaborate please? Other than that I hope the transplant will be a quick and painless affair.

Cheers, Dave C

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Zipperhead

  • The cyclist formerly known as Big Helga
Re: Help with frame related questions
« Reply #427 on: 03 January, 2017, 02:19:06 pm »
But the frame brake line guides look like they are for cable and I have hydraulic brakes. Any suggestions? I don't want to butcher the guides but there are slotted guides for tie wraps so this may be a possibility.

I used these when I converted my tandem to hydraulic brakes - Magura brake hose guides

They bolt into the existing cable guide and the brake pipe clips into them.
Won't somebody think of the hamsters!

Dave_C

  • Trying to get rid of my belly... and failing!
Re: Help with frame related questions
« Reply #428 on: 03 January, 2017, 11:02:37 pm »
Thanks Zipperhead! I recall seeing something like these before. Thanks for the help! :D

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Re: Help with frame related questions
« Reply #429 on: 03 January, 2017, 11:04:28 pm »
You can just cable-tie the hose on and use the existing stops as guides. It won't be that neat, but it'll work.


Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: Help with frame related questions
« Reply #431 on: 05 January, 2017, 08:31:13 pm »
I have to say my experience of those is less than sub-optimal.

Cleaned paintwork then degreased with solvent, dried and warmed the surface. Stuck for about 20 minutes. I think the manufacturers know this, that's why they come with zip ties, it's a tacit admission that they dont work...

ETA. Six anna half quid for three bits of plastic is scandalous!
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: Help with frame related questions
« Reply #432 on: 07 June, 2017, 08:06:05 am »
Having  crashed  through  a few potholes on a  600K perm on the  T T* machine this weekend and having broken a pair of Longstaff tandem forks in the past**  I  am thinking  of  taking them out of the frame and giving  them the 'ding and ring' test.

Having only seen this being done once by D.Y.  how hard and where should I ding and how do I preserve the paint? is this test, with my cloth ears worth it?

These are nice flexible forks. as  G.L. said to me 'these are yer front suspension'  you can see the blades flexing over bumps. However due to 'modern roads' the 28C tyre will be replaced with a 35C for LEL.

*some of this parish will know I  mean tandem trike not time trial  :)
** To be fair in that  instance the blade was not properly brazed into the crown - 'twas mostly held in with flux. Compare this with Georges overbuilt frame fillets... :-[



LittleWheelsandBig

  • Whimsy Rider
Re: Help with frame related questions
« Reply #433 on: 07 June, 2017, 01:10:40 pm »
You shouldn't be hitting the fork hard enough to chip paint off (or hitting the fork crown). Basically make a tink or ding sound up high (mostly) on the fork blades and be concerned if there is a noticeable difference between one fork blade and the other. If you are tone-deaf, there must be a smartphone app that recognises pitch. I know there are ones for guitar tuning.

Look really hard at the paint over brazed joints too.
Wheel meet again, don't know where, don't know when...

Re: Help with frame related questions
« Reply #434 on: 06 August, 2017, 10:53:39 am »
Query about bikes for light riders:
As most bikes are made for "the generic" rider with an addition to avoid liability, you often get posts on forums from powerful heavier riders looking for a frame to replace the series of frames that they have destroyed through being mighty and massive.
On the flip side, if you are a tall 65kg rider, might it make sense to have a bike built for you instead of for the heavier masses? (I know it's not that much lighter than average, but it is for say a 6'+ rider).
Would you get a bike that is not overly stiff out of it?
Would the bike be lighter?
Or is it a theoretical thing that wouldn't happen as it is too dependent on the narrow choice of tubing available?
Thanks.
simplicity, truth, equality, peace

Re: Help with frame related questions
« Reply #435 on: 06 August, 2017, 12:11:23 pm »
Aluminium is cheaper and sometimes lighter.
Carbon is usually expensive and lighter. Carbon soaks up vibration and bumps better than aluminium.

don't obsess over the material. Test ride some bikes and buy the one that feels right.

Close clearances are pointless, IMO.
I suspect you are associating them with snappy handling that feels fast.


Hi mrcharly. I personally have never ridden a Carbon frame - and my pension would not support such frivolous fashion.
Carbon is known for being a severe ride and very little kindly to the skeleton as a quality steel frame is.
Carbon is also known for sudden and inexplicable failures as it is also known for crushing if one is a little heavy-handed with Spanners and or Allen Keys.
Whether it be 531 single or double butted or even Columbus tubing - there is a comfort level that really does take some beating.

Rider weight and Saddle choice has a great-deal to do with rider comfort and as does bar/stem choice and the appropriate wrappings of bar-tape.

My road bike is a Steve Goff Columbus tubed - Designer Select - three different Columbus tubes chosen by Steve Goff for their particular attributes.
I have just built a Bianchi Via Nirone 7 Alu Carbon (Carbon Forks and Carbon Seat Stays) as a Flat-bar Road Hybrid on Campagnolo Veloce levers.
At almost 72yrs young the blend of 7000 Alloy and very little carbon is about as much as my old bones will tolerate on our crappy roads and with the comfort of the Flat-bars for a leisurely and upright ride.
Your ears are your rear-end defenders,keep them free of clutter and possibly live longer.

Re: Help with frame related questions
« Reply #436 on: 06 November, 2017, 07:18:48 pm »
Help needed , shim material for Airnimal telescopic seat tube reducing from 30.2 mm to 30mm . I thought s/s sheet epoxy resin glued in , but can only seem to buy in China . Any thoughts ?


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Re: Help with frame related questions
« Reply #437 on: 31 March, 2020, 10:22:45 pm »
So, on the way in to start my Deliveroo shift today this happened.



Cycling uphill and came to a stop at some lights and on starting off again got maybe 3 revolutions into it before the cranks wouldn't spin. Thought the chain had unshipped and jammed in the front derailleur but turns out a chainring bolt had snapped at some point and folded the chainring. The result is this....









A big gouge and a slight dent. Although the last photo there makes it look worse than it is, it's still looks fairly significant to my eyes. It's an aluminium Triban RC500. I'll get in touch with Decathlon tomorrow, but since they don't seem to sell framesets I'm not holding out much hope in getting hold of a cheap replacement and it doesn't seem like it would be a warranty issue either.

Am I right in thinking this frame is toast? Couldn't happen at a worse time. Do I chance it or just resign myself to the fact that I'll be budgeting for a new frame?

zigzag

  • unfuckwithable
Re: Help with frame related questions
« Reply #438 on: 31 March, 2020, 10:35:01 pm »
i'd ride it, but repair it too.

two wraps of ~5cm wide carbon fibre strip would keep the frame structurally sound.

Re: Help with frame related questions
« Reply #439 on: 08 April, 2021, 04:41:54 pm »
Hi all, I'm looking for a little bit of advice.

This is my second titanium frame that has cracked. The first was replaced under warranty by the supplier no quibbles (although it took over 7 months to get a new frame). The first time, the frame cracked around the holes for cable on the downtube - definitely a design fault which has since been addressed on the new frame.

The new frame has now cracked on the weld area between the headtube and downtube - just a small crack, which I spotted early on, but still a definite crack.
Does this look like it could be repaired (without an ugly weld), or is a replacement frame needed?

The supplier has however examined the frame and found a bit of wear on my non-drive rear stay.
It has a small dip into the rear stay when he rubs his finger over it - he's saying it's 'severe wear', I think it's more cosmetic.
Because of this however, this is their stance:

Even if our manufacturer can repair the head tube the seat stay has worn in such a way it now compromises the rear of the frame and we wouldn't want you riding a frame that we know is compromised at the rear.

My proposal is that we offer a replacement frame but as the current one can't be repaired due to the seat stay we would ask you to contribute 50% towards the cost of a new frame. We're happy covering the labour cost of switching all the parts or building up a new bike which is roughly £250 for a bike like this.


Surely the crack is the problem, if the crack can't be repaired (no matter if there is wear on the stay) the frame should be replaced - that's the manufacturer's error. If the crack can be replaced, then surely the wear on the stay is my problem, and if I decide it is just cosmetic, I could just keep using the frame. Obviously if it breaks at the stay, then it isn't the suppliers problem.

Any advice welcomed,
Thanks






Re: Help with frame related questions
« Reply #440 on: 09 April, 2021, 07:35:35 am »
Disclaimer: I am a mechanical engineer whose job includes spending time looking at photo's of damaged components and trying to understand what I am looking at - but they aren't bike frames (or even titanium).

The crack has run into the tube so any repair is more than just grinding out and redoing the weld.  It will be big(ger) and it may be ugly.  I would also be concerned about the longevity of the repair and the rest of the welds on the frame.

It is never easy to interpret photo's but to me the mark on the stay looks far closer to the 'cosmetic' end of the damage spectrum than the 'severe wear' end.  Fingers are remarkably good at feeling this sort of imperfection and, as a result, are also good at making it feel far worse than it is.  If the dealer is proposing to effectively write the frame off as a result of the mark I would expect them to provide some proper dimensional checks showing the extent of the damage and the amount of material removed and give an indication of the effect that this will have on the ability of the component to do its job.

I am not sure about the legalities of this but - assuming it is not possible/desirable to repair the original frame then it seems reasonable that you are asked to make a contribution to the cost of a new frame based on the wear and tear that you have applied to the original frame.  That contribution should be based on something more calibrated than the dealer's fingers.

Hopefully someone will be along in a bit who actually knows what they are talking about with respect to bike frames and warranties!

Re: Help with frame related questions
« Reply #441 on: 09 April, 2021, 01:20:20 pm »
Hi JonBuoy,

Thanks for your comments.

Confirmed most of my suspicions re the frame not being able to be repaired. Also, without seeing actual measurements of the wear in the rear stay, it is difficult to know if the frame has been significantly compromised in that area.

The frame is under warranty, so I'd have expected the frame to be replaced because of the crack. I feel the two issues should be seen as two separate items: the crack has definitely compromised the frames integrity whereas the wear hasn't yet (and if that wear is halted, the frame could still last a long time).

I'm being asked to contribute 50% of the price of a new frame - but I feel a fairer option would be 50% of the cost price of the frame, otherwise I am potentially footing the full cost of a new frame. (I of course, don't know what the true cost price is to the supplier).

Plenty to think about at this stage.

Re: Help with frame related questions
« Reply #442 on: 25 May, 2021, 06:49:44 pm »
Who is the frame supplied by?
There are a few manufacturers that have "previous" on using almost any excuse to avoid honoring the warranty!

zigzag

  • unfuckwithable
Re: Help with frame related questions
« Reply #443 on: 31 May, 2021, 03:35:05 pm »
how quick/easy is to make indentations on chainstays for tyre clearance on a steel frame? ideally without damaging the paint.


LittleWheelsandBig

  • Whimsy Rider
Re: Help with frame related questions
« Reply #444 on: 31 May, 2021, 03:41:11 pm »
Depends on the type of tubing.

A framebuilder friend of mine modified some vice grips to do so, with different sized/ shaped jaws to cradle the chainstay to avoid crimping the wrong side. There is a somewhat greater chance of initiating a crack down the road if you are too hamfisted.

How much movement do you need? A mm or two, no problem. 10mm, don’t be silly. Smooth curves are better for fatigue than hard folds or crimps, so gentle ovalisation is generally better than hammering in a reverse-curve dimple.

Expect paint damage as most paint isn’t flexible enough and chips or flakes under high contact forces.
Wheel meet again, don't know where, don't know when...

zigzag

  • unfuckwithable
Re: Help with frame related questions
« Reply #445 on: 31 May, 2021, 05:08:19 pm »
thank you, i agree with the best practices to not overdo this. currently there are no indentations at all, so adding ~5mm of clearance each side should be fine i would hope? if a piece of cloth was placed between the frame and dowel(?), would it protect the paint somewhat?

LittleWheelsandBig

  • Whimsy Rider
Re: Help with frame related questions
« Reply #446 on: 31 May, 2021, 05:17:58 pm »
Maybe but 5mm each side is a large percentage of the width of a chainstay. Are you using a vice (or similar hand tool) or a hammer and drift? One of those methods is more controllable.

Figure on the paint being trashed (regardless of protection) and perhaps be pleasantly surprised but I know what I would put my money on.
Wheel meet again, don't know where, don't know when...

Re: Help with frame related questions
« Reply #447 on: 31 May, 2021, 09:29:10 pm »
I indented a drive-side chainstay to clear a fooking great chainring on our racing tandem.  30yrs later it is still going strong.  Mostly a 531 tandem set as I recall.

Re: Help with frame related questions
« Reply #448 on: 01 August, 2021, 07:21:54 pm »
We have a second hand ally dirt jump frame arriving soon... Plan is to rattle-can it "raw" in clear-coat. Any advice about stripping? (Carry-On Camping jokes also welcome)

Our lad's idea is to Nitromors it...

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zigzag

  • unfuckwithable
Help with frame related questions
« Reply #449 on: 06 August, 2021, 06:28:02 pm »
so, took the frame along with my drawings to a local master frame builder who did a stellar job, even keeping the original paint intact (small spots of surface rust are from a long time before). the frame now clears 32mm tyre with at least 5mm space everywhere. chainstays were indented by 5mm, from 19.5 -> 14.5mm. well chuffed!