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by Brucey
12 May 2021, 3:59pm
Forum: Bikes & Bits – Technical section
Topic: 25mm inner tube in 28mm tyre
Replies: 14
Views: 844

Re: 25mm inner tube in 28mm tyre

in theory +10mm on circumference so no problem, right?

in practice it sometimes works ok, sometimes not.Try it and see.

cheers
by Brucey
12 May 2021, 3:05pm
Forum: Bikes & Bits – Technical section
Topic: Best wishes for Brucey
Replies: 507
Views: 33320

Re: Best wishes for Brucey

well here I am sat in Hospital, still alive (but not exactly kicking normally). I just wanted to thank everyone for their kind words and best wishes :however they might have been expressed. I would have responded be fore now but I have not been able.
My future participation here is in some doubt; more as time goes on.
cheers all
Brucey
by Brucey
11 Mar 2021, 5:19pm
Forum: Bikes & Bits – Technical section
Topic: Worn out Mavic Open Pro. non disc
Replies: 15
Views: 886

Re: Worn out Mavic Open Pro. non disc

ANTONISH wrote:I have several wheels built with open pro rims.
The rims on one set are showing signs of wear and due to the thin braking surface I've decided to replace them.
Are there any suggestions of a suitable replacement -preferably symmetric, silver and 36h- not a lot heavier than the open pro ?
( although given the speed that I ride at these days the weight probably won't make a lot of difference).
I use 28mm gatorskins in good weather and 28mm 4 seasons in the winter.


Exal XR2 may work for you

https://www.spacycles.co.uk/m20b0s116p1567/EXAL-XR2

although they are showing stock of Black 36h only at present.

The stated ERD is 606mm which compares with 604.5mm for Open Pro (which is my average having built dozens of them) which should mean a simple re-rim (i.e. using the original spokes) ought to be possible, provided the spokes were not a bit short for the Open Pros to begin with.

Ambrosio also do a couple of rims that could work for you (eg 'Excellence') but I'm not quite sure how good the ERD match is; the usual mix of ERD values ranging from 601.5 to 603.5mm seems to be available... :roll:

cheers
by Brucey
11 Mar 2021, 4:58pm
Forum: Bikes & Bits – Technical section
Topic: Dawes Mojave project:- front wheel needed
Replies: 13
Views: 457

Re: Dawes Mojave project:- front wheel needed

V8rumbler wrote:how hard is this? is there a guide somewhere?


not hard at all, really. And if you were thinking of replacing the wheel anyway the only thing you have to lose is a little of your time and perhaps the cost of a spoke key.

This is pretty much all you need to know for a lateral runout;
Image

The link below is full of useful information but is probably a bit OTT for a first timer.
https://www.parktool.com/blog/repair-help/wheel-and-rim-truing

Fundamentally wheels go out of true for two main reasons; either the spoke tensions have changed -or spokes have actually broken- (and the rim is still basically straight if it is free of the spokes) or the rim is bent (i.e. it won't be straight when free of the spokes) and an uneven spoke tension is required to bring it straight. If the latter, then a few mm can be corrected by truing, but bigger problems with the rim can't always be corrected using spoke adjustments.

cheers
by Brucey
11 Mar 2021, 4:43pm
Forum: Bikes & Bits – Technical section
Topic: Headset Detent
Replies: 29
Views: 1405

Re: Headset Detent

531colin wrote:
Brucey wrote:with an A-head headset a major source of settling can be in the wedge part (where fitted). It is not unusual for this to settle and require several adjustments.

cheers

They settle on titanium bikes..... no paint!


IME the wedge settles on the steerer to some extent, regardless of the materials involved (in both wedge and steerer). I have seen quite a few carbon steerers badly worn where the wedge didn't stop moving around in service.... :shock:

cheers
by Brucey
11 Mar 2021, 4:32pm
Forum: Bikes & Bits – Technical section
Topic: Shimano freehub body internals
Replies: 63
Views: 2602

Re: Shimano freehub body internals

nsew wrote:

There isn’t “plenty of room”, in fact there’s no room. Your method acknowledges there’s no room because in order to lubricate the mechanism the hub has to be flooded with oil to lubricate a separate mechanism. That much is bleeding obvious.


wrong again.

Look: I have been lubricating freehubs this kind of way for over thirty years. You are busy telling me I am wrong when you have not even tried it.... :roll:
by Brucey
11 Mar 2021, 11:31am
Forum: Bikes & Bits – Technical section
Topic: Holdsworthy 'Allez' (Takagi) chainsets
Replies: 7
Views: 472

Re: Holdsworthy 'Allez' (Takagi) chainsets

examples of other (much older) 'Allez!" branded products;

Image

Image

cheers
by Brucey
11 Mar 2021, 9:13am
Forum: Bikes & Bits – Technical section
Topic: Headset Detent
Replies: 29
Views: 1405

Re: Headset Detent

with an A-head headset a major source of settling can be in the wedge part (where fitted). It is not unusual for this to settle and require several adjustments.

cheers
by Brucey
11 Mar 2021, 9:06am
Forum: Bikes & Bits – Technical section
Topic: Shimano Nexus 7; how it works. (long)
Replies: 39
Views: 23820

Re: Shimano Nexus 7; how it works. (long)

I think that will be fine

cheers
by Brucey
11 Mar 2021, 7:03am
Forum: Bikes & Bits – Technical section
Topic: Holdsworthy 'Allez' (Takagi) chainsets
Replies: 7
Views: 472

Re: Holdsworthy 'Allez' (Takagi) chainsets

Takagi BMX cranks, circa 1980

Image

Apparently they are well regarded in BMX circles.

cheers
by Brucey
10 Mar 2021, 11:59pm
Forum: Bikes & Bits – Technical section
Topic: Holdsworthy 'Allez' (Takagi) chainsets
Replies: 7
Views: 472

Holdsworthy 'Allez' (Takagi) chainsets

In about 1984 or 1985 I stumbled into my LBS and enquired about a triple chainset, because a tour to the alps was in the offing. They offered me an 'Allez' chainset; I'd seen these chainsets fitted to various Holdsworthy bikes (Claud Butlers and Holdsworths mainly) mostly as doubles and whilst it wasn't my first choice it seemed OK to my eyes; not a TA triple, but then I couldn't afford one of those anyway, whereas this one was more like it, price-wise, being a bit strapped for cash at the time: I think it was about £30, including BB. I nearly didn't buy it because of the ring sizes fitted (which seemed a bit odd to me) and because the chainrings had odd bolt circle measurements I hadn't previously encountered. If I could have found one I liked at the right price I would happily have bought a 144/something triple, since I already had a fair stash of 3/32" 144BCD chainrings from my road bike and various fixed gear bikes.

But 'that'll do' I thought, and for no other reason than it might involve spending money otherwise I decided to give the rings that were fitted a shot; 50-44-32 it was, then. And the 'funny bolt circles' were 5x 110/74mm; rare then but they soon became almost ubiquitous. Well that chainset has been on at least three different framesets since then and through it all is has been my main touring chainset. And whilst I swapped the 32T for a 30T sometimes I never did bother to change the other chainring sizes, but instead came to understand and appreciate the ones I had.

Today I was sorting out some stuff and I came across my 'spare chainset' which I picked up at a cycle jumble a few years ago; the same cranks but configured as a 48-36 double.

Holdsworthy 'Allez' (Takagi) chainset, 48-36T
Holdsworthy 'Allez' (Takagi) chainset, 48-36T

Holdsworthy 'Allez' (Takagi) chainset, 48-36T
Holdsworthy 'Allez' (Takagi) chainset, 48-36T


You can see that the 36T ring has a substantial chamfer on it, because it is meant to be the middle ring of a triple. I might yet fit a third ring to this and make it a 48-36-24 triple.

Whilst cleaning them I noticed the words "Takagi Japan". I must have seen this before but it probably didn't register then. Takagi were an independent Japanese manufacturer of cranks and according to this page

https://www.sscycleworks.com/components/cranksets-Takagi.html

had been making cranks since 1897. They made cranks under their own Takagi brand and 'three arrows' brand as well as for Holdsworthy (I didn't know this then but their "Allez!" brand name had been applied to all kinds of third party products Holdsworthy sold for decades) but their main outlet was probably production for shimano. So if you bought an early set of Dura-Ace cranks (for example) you got Takagi manufactured cranks. [They made some pretty nice BMX cranks too, and even shimano got in on the act; somewhere I have a set of DA 7200 cranks which were sold as a BMX chainset; they are anodised bright red! ] Sometime in the 1980s Takagi were bought lock stock and barrel by shimano and the Takagi brand was dropped. Shimano started 'making' some really rather good 110/74 triple chainsets and the rest is history. In reality very similar cranks (give or take) had been on sale with Takagi branding (eg in the US) or with 'Allez' branding in the UK for some years.

When Deore XT 'deer head' was one of the best gearsets available, not everyone was convinced by shimano's dyna-drive cranksets. A lot of bike manufacturers fitted a Takagi 110/74 triple instead for the US market. There were models with names such as 'Tourney XT' and 'Tourney GS', which sound like shimano models but they weren't, they were Takagi models. They come up for sale in the USA fairly often eg

https://thea.com/Cranksets-Takagi-Tourney/

One of which is almost identical to the "Allez" branded cranks. Some of these are dead ringers for sugino branded models too; whether there is any link there or not I don't know. It seems Sugino, Specialized, SR-Sakae (SunTour) and Takagi all came out with very similar cranksets at about the same time.

So it isn't clear to me who 'invented' the 110/74 arrangement but Takagi were certainly in it almost from the start. And whilst I was almost looking down my nose at my 'Allez' chainset, BITD, in reality I was falling on my feet; If I'd have had more money I would probably have ended up with something worse....! :shock: :shock:

cheers
by Brucey
10 Mar 2021, 9:34pm
Forum: Bikes & Bits – Technical section
Topic: Shimano Nexus 7; how it works. (long)
Replies: 39
Views: 23820

Re: Shimano Nexus 7; how it works. (long)

That all sounds encouraging apart from the cleaning and relubing; you will probably have re-lubed most of the gear parts this way. However what you won't have done is lubed the RH hub bearing and the shift control mechanism (again in the RHS of the hub). If you have used a solvent degreaser on the hub internals and cleaned the lube out of the RHS of the hub, I would strongly suggest that you add gear oil to the SFG inside the hub in sufficient quantity that it definitely does penetrate the entire mechanism in the RHS of the hub. This is easily done with the hub in bits again but it can instead be added via the LHS of the hub once the LHS cone is removed.

The RH hub bearings are prone to failure anyway and washing all the grease out of them without replenishing it is asking for trouble.

cheers
by Brucey
10 Mar 2021, 9:10pm
Forum: Bikes & Bits – Technical section
Topic: Shimano freehub body internals
Replies: 63
Views: 2602

Re: Shimano freehub body internals

there is plenty of room for oil to penetrate the freehub mechanism without removing the freehub dustcap. Removing the freehub dustcap is a waste of time unless you intend to reshim the bearings. As I mentioned previously it just takes a bit longer for SFG to penetrate the mechanism, and 'oil first' is the best way. If the oil mixes with a little of the original grease it is no big deal.

If you add oil to the RHS a hub which has standard grease in it and run it for a few hundred miles it will sort itself out such that a second visit will require the addition of SFG only and that will be all that is required for the next year or so.

FWIW in service, any lube which is mobile enough is centrifuged outwards from the hub bearing through the freehub body. As I mentioned previously if there is no seal on the LHS of the freehub body and if the lube is thin/plentiful enough then it can come out and make a bit of a mess, but in so doing it flushes crud out too, so it is not all bad. With SFG and/or a seal on the LHS of the freehub body the rate of loss can be low enough that it doesn't worry most folk; a drop in an ocean of chain lube, more or less.

Some rough calculations suggest that at normal speeds the lube sees a centrifugal effect that is between 1.5G and 2G. During downhill runs at about double normal speed, these forces are x4 so up to ~8G

IIRC CJ has long used a grease gun on his freehubs (via a drilled hole in the hubshell) and ISTR he has mentioned that he hasn't had to take one apart in several decades. When I have done this the hub has ended up overfilled and in subsequent use excess grease usually emerges and needs to be cleaned up. CJ reported no pawl problems even with #2 grease which may indicate that grease takes the path of least resistance, i.e. when the grease gun is used, the grease blows out of the hub end seal before it is pushed through the freehub body wholesale. Many greases, in quantity, will separate (especially if they see 8G from time to time) and I have always supposed it is quite possible that CJ's freehub bodies are in effect lubed with oil which has bled out of the grease.

The same thing won't happen with 'normal' greasing, simply because the quantity of grease is much smaller so there is simply less oil present to bleed out. Nonetheless it is noticeable that the grease in the RHS of conventionally maintained freehubs is often a fair bit drier than the grease in the LHS of the same hub, so some 'bleeding' and consequent loss (via the freehub body) has presumably occurred.

cheers
by Brucey
10 Mar 2021, 8:35pm
Forum: Bikes & Bits – Technical section
Topic: Finicky locks in winter...?
Replies: 23
Views: 861

Re: Finicky locks in winter...?

Stevek76 wrote:
The shape of the sidebar & gates can vary. From the one kryptonite I have seen in bits the sidebar was a cylinder/rod and the gates were circular so a fairly large amount of tolerance. They are not as high quality as the abloy locks.

The disc would really need to be more than half a gate width out to prevent the lock from turning else the sidebar being pressed in will align the disc the rest of the way.

That degree of misalignment should mean significant/visible key or disc damage which makes the recovery of the lock to start working fine again very curious.


that is interesting. Maybe I should dismantle such a lock; I think I have a scrap one somewhere. I agree that it is rather odd that the keys were not marked and that the lock somehow 'recovered'!

cheers