Grant Petersen’s Rivendell Roadini

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Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Grant Petersen’s Rivendell Roadini

Postby Brucey » 7 Jan 2019, 9:47am

its worth mentioning that BB height is fixed once you have bought your frame (and chosen your tyres) but it is just one of several things that affects pedal/crank ground clearance.

Tyres can make a big difference; realistically up to 20mm if you are going offroad
Crank length; choosing between 170 and 175mm makes 5mm difference
Crank eye design; about 5mm difference (even with the same crank length) between cranks eg because some cranks are made the same whether they are drilled 170mm or 175mm. Some crank ends get bashed into the rocks on a regular basis because they are that bit longer than others.
Pedal thickness; at least 10mm variation depending on pedal design
Pedal width; doesn't affect vertical clearance per se but does affect your chances of pedal strike.

so variations in these things are probably at least as important as BB height per se; you could easily have two riders on 'the same bike' (frame) who have about 35mm difference in pedal to ground clearance

cheers
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Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: Grant Petersen’s Rivendell Roadini

Postby Brucey » 7 Jan 2019, 9:54am

reohn2 wrote:….I don't think it actually came loose but more as a new bike had settled in....


I'm probably not alone in struggling to see what the difference is between these things. IME Ahead headsets are many times more likely to come loose and give trouble this way. As I mentioned upthread, the addition of a simple component costing mere pennies could make this far less likely; that this isn't fitted tells you everything you need to know about the forces at work here....

cheers
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reohn2
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Re: Grant Petersen’s Rivendell Roadini

Postby reohn2 » 7 Jan 2019, 10:09am

Brucey wrote:
reohn2 wrote:….I don't think it actually came loose but more as a new bike had settled in....


I'm probably not alone in struggling to see what the difference is between these things. IME Ahead headsets are many times more likely to come loose and give trouble this way. As I mentioned upthread, the addition of a simple component costing mere pennies could make this far less likely; that this isn't fitted tells you everything you need to know about the forces at work here....

cheers

The FSA headset on my Genesis Longitude,3 years old and only ridden off road,hasn't needed adjusting more than once,and I can't remember ever adjusting the Hope one on my Salsa Vaya which is 7 years old and ridden both on and off road.Both Ahead.
Headsets on both bikes are checked regularly for smoothness and play.

I'm not counting the many miles covered on the tandems with Aheadsets that have given me no trouble at all in the past 20 years :)
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amediasatex
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Re: Grant Petersen’s Rivendell Roadini

Postby amediasatex » 7 Jan 2019, 10:13am

Not to mention the impossibility of getting a 35mm tyre and mudguard under a dual pivot sidepull in the first place.


Not with 57mm drop brakes no, but with the 73mm drop Tektro (R559?) it's perfectly doable, they're not quite as good as the (57mm) Shimano 650s but they're not bad brakes and do give you bigger tyre options on bikes that have the room, or for 650B conversion on 700C frames.

The FSA headset on my Genesis Longitude,3 years old and only ridden off road,hasn't needed adjusting more than once,and I can't remember ever adjusting the Hope one on my Salsa Vaya which is 7 years old and ridden both on and off road.Both Ahead.
Headsets on both bikes are checked regularly for smoothness and play.


I'm not going to get too into this as I cna see the thread already starting to degenerate into a headset arguement, but there are numerous bikes out there with threaded headsets that are a half century old or more, on their original bearings and only ever adjusted a handful of times.

The key, as always is to do it properly (and having components of decent quality). It's entirely possible to make a well sealed threadless headset, and adjust it properly so that it lasts for many years. It's also easy to adjust a threaded headset badly, but in the real world with 'normal' users is a lot easier to cock up a threadless setup, neither *should* come loose in normal use, but you can un-adjust a threadless one very easily, and you have to to change stems/height etc, where as with a threaded setup once it's set right, it's set and you can meddle with everything else independently. I happily use both without issue, I know what I'm doing with them though and largely it comes down to preference and what you already have experience of and there are far better things to disagree about ;-)

Brucey
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Re: Grant Petersen’s Rivendell Roadini

Postby Brucey » 7 Jan 2019, 10:40am

it is as well to note that you can have a preference for one or the other and YMMV as to how well they work for you; there are good and bad examples of both types. It would certainly sway me when buying a bike. But for it to turn into a 'show stopper' (as some have suggested might be the case for them in this thread) on this kind of bike would definitely be a mistake IMHO.

cheers
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JakobW
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Re: Grant Petersen’s Rivendell Roadini

Postby JakobW » 7 Jan 2019, 10:44am

I think the R559s were designed at Grant's behest specifically to accommodate Rivendell's (massive, gappy) clearances and then sold more widely by Tektro. I'm not entirely sure why he prefers sidepulls to cantis, which would be more common on wide-clearance bikes, but the 559s reportedly work pretty well.

Brucey
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Re: Grant Petersen’s Rivendell Roadini

Postby Brucey » 7 Jan 2019, 11:07am

I will put in a good word for Velo Orange DPs; not cheap and only 57mm (some say 59mm) reach but they are at least wide enough to accept a decent mudguard. I think you could fit some 32mm tyres and mudguards beneath them if the full reach is used.

Image

If they did the same brake with 5 or 10mm more reach they would be fine with 35mm tyres.

I will also put in a good word for cantis and centre pulls eg

Image

which can be very effective stoppers too. Just not very trendy at the moment....

cheers
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peetee
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Re: Grant Petersen’s Rivendell Roadini

Postby peetee » 7 Jan 2019, 11:11am

Brucey wrote:
peetee wrote:The world is also awash with A-headset bikes that have improperly adjusted bearings. I would estimate about 50% of A-head bikes appearing in my workshop fall into this category. There are a number of reasons for this but in the majority of cases I see it's because owners have adjusted the height of their bars without knowing the right way to do it. It's a very ingenious system but for the most part the advantages are cheaper assembly and manufacturing costs for the bike companies. The disadvantage is that adjustment is counter intuitive to anyone used to quill stems.


I agree.

However I would describe the adjustment as being counterintuitive to anyone including trained engineers. The intention is to provide a controlled preload to the bearings; a more half-assed approach to doing this would be difficult to conceive of. For a (mass production) cost of about 1p you could add a wave washer to the spacer assembly, or a Belleville washer to the top cap, or something like that. The procedure would then be to nip the preload bolt up and then back it off 1/4 turn (say). You certainly wouldn't be any worse off than at present either.


Fundamentally having the headset bearing setup tied to one of the adjustments that an 'untrained user' is going to want to make is a catastrophically stupid idea. Almost as stupid as having a system that requires you to buy a new stem if you want to make a meaningful change in the height of the handlebars.... :roll:

cheers


+1. I wanted to be as critical but wasn't prepared to take the flack. :lol:

We haven't even mentioned the simple fact that the demise of the threaded headset was undoubtedly hastened by the fact that it is utterly impossible to incorporate one on a carbon steerer. And who doesn't need one of them? 8)
On the subject of hastened, it wouldn't be the only example of bike tech that has introduced a high level of User-Induced-Premature-Replacement Syndrome.
Current status report:
Latter side of fifty and feeling less than nifty.
Too many bikes on pegs and too few miles in the legs.

slowster
Posts: 939
Joined: 7 Jul 2017, 10:37am

Re: Grant Petersen’s Rivendell Roadini

Postby slowster » 7 Jan 2019, 11:30am

amediasatex wrote:
Not to mention the impossibility of getting a 35mm tyre and mudguard under a dual pivot sidepull in the first place.


Not with 57mm drop brakes no, but with the 73mm drop Tektro (R559?) it's perfectly doable, they're not quite as good as the (57mm) Shimano 650s but they're not bad brakes and do give you bigger tyre options on bikes that have the room, or for 650B conversion on 700C frames.

I would add a word of warning that if you are getting a custom builder to build a frame to use with a brake like the R559 because you want to use 35mm tyres, or possibly even wider, be aware that the selection of fork crown will be crucial. I have a custom frame with Tektro deep drop brakes, and the distance between the inside tangs of the fork crown limits the tyre width to 32mm. In other words, the maximum tyre size needs to be explicitly discussed and agreed on with the builder in advance (which I failed to do).

As for ahead vs quill stems, my twopennyworth is that ahead stems with clamp plates do make it a bit easier to experiment with the handlebar height and reach and with different handlebar shapes and widths, whereas it is a bit more fiddly to swap around bars using quill stems. Look used to make an adjustable stem (I think in ahead as well as quill version), which could be replaced with a fixed quill stem once experimentation had determined the preferred bar height and reach. However, for steel framed road bikes once you have settled on your preferred stem height and length, I think a quill stem is aesthetically and functionally superior.

On a narrow tubed steel frame, mass produced modern ahead stems look awful, because they are out of proportion to the frame tubes. When ahead stems were introduced for road bikes, there was a short period when they were sized for 26mm clamp bars and 1" steerers, and those stems looked reasonably in proportion, e.g. Deda Newton 26 or ITM Millenium. The only other option for a modern bike with narrow tubes and a threadless steerer, would be to get the frame builder to make a custom ahead stem.

IMO, the biggest problem with ahead stems on a road bike, is the awful compromise that has to be made between aesthetics vs. future adjustibility. If you leave enough of the steerer uncut to be able to make significant changes to the height of the bars, e.g. due to decreasing flexibility or simply a change in preferrred riding position, the exposed section of steerer/spacers above the stem looks naff. Moreover, if the steerer is carbon, then having 20mm or more spacers above the stem will mean that any bung with a lip that sits on top of the steerer will not be properly positioned, i.e. it should extend to the same depth as the bottom of the stem or lower (and most stem manufacturers insist on this in their installation instructions).

amediasatex
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Re: Grant Petersen’s Rivendell Roadini

Postby amediasatex » 7 Jan 2019, 11:43am

Brucey wrote:I will put in a good word for Velo Orange DPs; not cheap and only 57mm (some say 59mm) reach but they are at least wide enough to accept a decent mudguard. I think you could fit some 32mm tyres and mudguards beneath them if the full reach is used.


I can confirm that you can fit a true 32mm tyre with acceptable* clearance under GB 40mm guards** with the VO brakes. It requires careful fitting to maximise clearance, and you have to be picky about either direct mounting to the brake bridge (if fittings exit) or using a low profile wrap around bridge mount but it does fit.

* to me
** I also think they would work with 45mm guards of similar profile , ie: rounded like VO/GB etc. rather than squared off like many SKS guards.
Last edited by amediasatex on 7 Jan 2019, 11:50am, edited 1 time in total.

amediasatex
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Joined: 2 Nov 2015, 12:51pm
Location: Sunny Devon! just East of the Moor

Re: Grant Petersen’s Rivendell Roadini

Postby amediasatex » 7 Jan 2019, 11:45am

slowster wrote:
amediasatex wrote:
Not to mention the impossibility of getting a 35mm tyre and mudguard under a dual pivot sidepull in the first place.


Not with 57mm drop brakes no, but with the 73mm drop Tektro (R559?) it's perfectly doable, they're not quite as good as the (57mm) Shimano 650s but they're not bad brakes and do give you bigger tyre options on bikes that have the room, or for 650B conversion on 700C frames.

I would add a word of warning that if you are getting a custom builder to build a frame to use with a brake like the R559 because you want to use 35mm tyres, or possibly even wider, be aware that the selection of fork crown will be crucial. I have a custom frame with Tektro deep drop brakes, and the distance between the inside tangs of the fork crown limits the tyre width to 32mm. In other words, the maximum tyre size needs to be explicitly discussed and agreed on with the builder in advance (which I failed to do).


Some might say it is the job of the builder to understand such things and ask those questions, and thus his (or her) failing, not yours.

peetee
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Re: Grant Petersen’s Rivendell Roadini

Postby peetee » 7 Jan 2019, 12:09pm

Without wishing to comment on the skills inherent in this company I have to say that it is a bit of a marketing faux-pas to allow the bikes to show handlebars and seat stems in over-extended positions.
Current status report:
Latter side of fifty and feeling less than nifty.
Too many bikes on pegs and too few miles in the legs.

slowster
Posts: 939
Joined: 7 Jul 2017, 10:37am

Re: Grant Petersen’s Rivendell Roadini

Postby slowster » 7 Jan 2019, 12:14pm

amediasatex wrote:
slowster wrote:
amediasatex wrote:
Not with 57mm drop brakes no, but with the 73mm drop Tektro (R559?) it's perfectly doable, they're not quite as good as the (57mm) Shimano 650s but they're not bad brakes and do give you bigger tyre options on bikes that have the room, or for 650B conversion on 700C frames.

I would add a word of warning that if you are getting a custom builder to build a frame to use with a brake like the R559 because you want to use 35mm tyres, or possibly even wider, be aware that the selection of fork crown will be crucial. I have a custom frame with Tektro deep drop brakes, and the distance between the inside tangs of the fork crown limits the tyre width to 32mm. In other words, the maximum tyre size needs to be explicitly discussed and agreed on with the builder in advance (which I failed to do).


Some might say it is the job of the builder to understand such things and ask those questions, and thus his (or her) failing, not yours.

In the builder's defence, it was I that chose the fork crown (purely for its looks: there were various example frames in the shop, and I liked the appearance of that particular sloping crown). I agree that a good frame builder* should have pointed out that that fork crown would limit the tyre width to 32mm, given that otherwise the Tektro deep drop brakes would allow tyres that were quite a bit wider. Fortunately it did not much matter: 32mm was and is the maximum tyre size I want to use on that bike.

* As it happens, it was one of the frame builders widely regarded as one of the best in the UK. Hence in part my posting my experience as a cautionary tale. No matter how good the reputation of the builder, it's best to be as thorough and precise as possible when discusing a new frame with a custom builder. I told the builder I wanted a fast road touring frame, and at that time (approximately 10 years ago) there was not the choice of very wide fast tyres that exists today, so arguably it was not unreasonable to assume that 32mm would be as wide as I would fit.

amediasatex
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Re: Grant Petersen’s Rivendell Roadini

Postby amediasatex » 7 Jan 2019, 12:16pm

peetee wrote:Without wishing to comment on the skills inherent in this company I have to say that it is a bit of a marketing faux-pas to allow the bikes to show handlebars and seat stems in over-extended positions.


Do you mean over-extended in the safety sense or aesthetic sense? I'm not a fan of the latter look myself, but I believe GP has a thing for using Nitto Technomic and Tallex stems which have a massive quill so can *look* over extended while actually being well within their design remit.

peetee
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Joined: 4 May 2010, 10:20pm

Re: Grant Petersen’s Rivendell Roadini

Postby peetee » 7 Jan 2019, 12:34pm

Fair enough, the handlebar stem 'looks' over extended but the seat post on the blue bike definitely shows the minimum insertion engraving.
Current status report:
Latter side of fifty and feeling less than nifty.
Too many bikes on pegs and too few miles in the legs.