Cycling UK Forum

Gattonero wrote:

Brucey wrote:I agree that rim brakes may well make more sense on a bike like this. By all means compare the two different bikes to see for yourself but IME there is a good chance that the rim brake model will ride better than the disc brake model. It is liable to work out this way because the loads that the fork has to see are completely different and this usually makes the disc fork an appreciably stiffer thing than a comparable rim brake fork....

Nah, I've ridden both and they ride the same

Which one do you have?

I suppose there's always the option of changing the fork and going for an hybrid disc/rim setup in future, right?

in fairness not everyone will agree about differences in ride quality, hence my suggestion that you try both rim and disc braked versions and see for yourself.

Regarding rim brake wear; there are a few wheels/rims which have pathetically thin braking surfaces and there are a few that have thicker ones. But the majority of rims have a braking surface thickness in the range 1.35 to 1.5mm, regardless of whether that rim is a touring or racing model.

cheers

garibaldi wrote:

Gattonero wrote:

Brucey wrote:I agree that rim brakes may well make more sense on a bike like this. By all means compare the two different bikes to see for yourself but IME there is a good chance that the rim brake model will ride better than the disc brake model. It is liable to work out this way because the loads that the fork has to see are completely different and this usually makes the disc fork an appreciably stiffer thing than a comparable rim brake fork....

Nah, I've ridden both and they ride the same

Which one do you have?

I suppose there's always the option of changing the fork and going for an hybrid disc/rim setup in future, right?

Mine is a custom one, essentially a rim-brake one but with the disk rear dropouts and straight seatstays. But I've ridden a few times a standard one before ordering mine. Then I tried the standard disk model and can't really feel any difference, surely it wasn't relevant to the point of making a not about. I'm lucky enough to have several bikes, so the "new thing excitement factor" is pretty low and I can feel differences right away across different bikes or setups.

just thought I'd add another comment to this thread. Just yesterday I was looking at a fairly recent (well used but also well cared for) Fratello, built in the multishape dedacci tubing, mostly TIG welded but with some brazed joints too (eg at the dropouts). The owner gets it maintained/serviced in the LBS but does basic stuff (chain maintenance, cleaning etc) themselves. The bike is always scrupulously clean (wiped rather than washed at a guess, judging from the odd bits of dirt behind the chainset etc) whenever it appears in the LBS. I thought it was a pretty tidy bike.

However whilst the paint job looked to be holding up well elsewhere, it looked to me like the paint was starting to blister on the seatstays, just above the brazed joints to the dropouts. Now this might be something to do with the conditions that this particular bike has seen, but I don't think it is that likely, judging from the condition of the rest of the bike.

However I have seen identical blistering/corrosion when flux deposits are not fully removed from brazed joints, so that seems the most likely cause to me. I don't know if this is commonplace on this model or not.

cheers

(OT) are such flux deposits not removed by frame blasting prior to painting, or do you need to do more? I've seen framebuilders' pictures of freshly-brazed frames soaking in a bathtub before, ostensibly to remove flux...

IME if the flux deposits are thick enough, they just ping off as the frame cools. Others are removed during shot blasting, and/or by soaking in water or dilute acids. Different methods work better with different fluxes.

However there are some flux residues that turn glassy during brazing, don't ping off, and resist various removal methods surprisingly well. If not removed, any remnants eventually soak up moisture and can start corrosion, even beneath a paint film. By and large the more effective the flux, the greater the capacity of residues to cause corrosion; so fluxes that work well with stainless steel are more corrosive than ones meant for ordinary steels.

[edit; to clarify, flux for brazing varies from something that is pretty inert, so prevents oxidation of clean parts, all the way to extremely aggressive fluxes which will attack and breach the oxide layer even on stainless steel. The former type of flux can still allow good brazing if the braze metal itself starts to dissolve the underlying steel at the brazing temperature; this happens with most materials which are used for so-called 'hard brazing' of steel, hence joints that are heated too much and/or for too long can be weakened by the braze metal attacking the underlying steel. Typically the braze metal first penetrates along the grain boundaries in the steel; if this happens much the steel itself is weakened. At lower temperatures (eg when using silver based braze metals) such effects are greatly reduced.]

cheers

Brucey wrote:I abhor the waste implicit in using wheelsets which don't have readily replaceable rims; rims may wear out but decent hubs and spokes ought to last almost indefinitely.

cheers

well said brucey - I have a pair of XT hubs on their second rims and a second bike.

the re-rimming/wheeling was done by a nice local bike shop. Now I just need to learn to build wheels.

I looked at the Fratello frameset recently when deciding what to buy and build for my next bike. Looks very nicely made but the tubing used is very lightweight (Columbus Spirit) and I decided against as I'd have to have bought the 64cm size to avoid toe overlap and I didn't think it would be stiff enough in my size. I guess depending on the size you need and your own weight you might want to consider that factor if planning any touring with significant loads.

Also my guess is the titanium frame would be more tolerant to dents/impacts and obviously won't be compromised by corrosion (which could affect a very thin-walled steel-tubed frame).