Questions on a Genesis Vagabond built

[geomannie]

Hi All

I am progressing with my build and have hit a couple of wrinkles as I thought I might. I'd be really grateful for thoughts.

1. I have decided to run a triple (Spa Cycles TD2) with 46/34/24. I have installed the recommended UN55 which is 113mm. When installed, the 24T inner is only about 1mm from the chainstay. Is this too close or is a miss as good as mile? The chainline looks good. If its too close, should I install a (say 1mm) spacer on the drive side of the BB or replace with a different BB?

2. It was suggested to me that a Sora triple front deraileur would work which was good because I have one in my parts box. Fitting it however, the bottle boss stops me putting it as low as I would like. There is about a 9-10mm gap to the top of outer chain ring. Is this ikely to be acceptable? The Sora front derailleur also extends quite far back and is only 5-6mm from the rear (50mm) tyre. Seems a bit close. My question I suppose, what FD might be better. I note that reohn2 is using a Tiagra FD 4503 but is this fundamentally different to the Sora?

3. And for something completely different, I will need to cut the steerer. Is this simple a home job in my vice?: should I get the fancy cutting jig?: should I take it to my LBS?: Is it right that you cut 3mm below the desired length (as I've seen suggested)?

Thanks a bunch folks

B

[reohn2]

1) a 118mm BB will solve the 1mm inner ring to chainstay gap,at the expense of the chainline being 2.5mm further out,which isn't much if the mech will move that much further over,easily checked by checking how much more there is left on the outer limit screw.But I think you're safe.
Front mech being high wouldn't worry me at all,here's mine which changes perfectly with a full 10mm gap,though as you can see in the photo the mech is an Ultegra FD6603 and not a Tiagra as I thought.I got mixed up between the Vagabond and my Vaya,which has the same chainset and the same gap between outer cage and chainring and again changes perfectly.The limit that prevents me lowering the mech further is the chainstay to mech tail gap with the 42t outer ring.
Photo(click on image for a larger pic):-

The puzzle is why the inner tail of the mech is so close to the tyre,mine has a 10mm gap with a 50mm chainline, that said a 118mm BB will move the inner mech limit 2.5mm further out.

3)I cut steerers with a hacksaw following a wrap of tape stuck on square around the steerer and deburred with a file

[PH]

3. And for something completely different, I will need to cut the steerer. Is this simple a home job in my vice?: should I get the fancy cutting jig?: should I take it to my LBS?: Is it right that you cut 3mm below the desired length (as I've seen suggested)?
B

I use a pipe cutter. though a hacksaw is likely to do just as well. Yes you need a gap, the top cap needs to be pressing on the stem or spacer and not bottom out on the steerer. I leave a 10mm spacer above the stem, just for a bit of future adjustability.

[reohn2]

Thinks.... .....re the inner cage to tyre gap,is the mech set up properly(there's no chain the bike in the photo)could it be the mech inner limit screw needs tweeking once the chain's on?
The point is slightly moot as if you're not comfortable with inner ring so close to the chainstay,and wouldn't blame you,and you fit a longer BB that will only help the situation.

[reohn2]

.......Yes you need a gap, the top cap needs to be pressing on the stem or spacer and not bottom out on the steerer. I leave a 10mm spacer above the stem, just for a bit of future adjustability.

Yep,spot on
I forgot to answer that bit

[peterh11]

I installed a 24/34/46 TD-2 triple on my tourer recently. I am using a 116mm BB (First Components) and it is perfect. The chainline is between 44 and 45mm, the inner face of the right hand crank has a few mm clearance, and the inner chainring is between 1 and 2 mm from the chainstays. The chainstays are fairly wide to accommodate up to a 50mm tyre (mine are 37mm as measured). You might need to go further out for a 50mm tyre, ask me and I will measure the clearance to give you an idea.

I used a torque wrench on it and have it around 35Nm or so.

I have ridden a couple of hundred kilometers on it now, no problems so far.

My experience is that a 113mm BB is too short for this chainset, at least on my frame. I had that initially (as recommended) and I couldn't tighten it up without the inner chainring and inner face of the crank touching the frame. (I started a thread a few weeks ago on this, just search on my username). You will get away with it, with a frame with narrow chainstays, but you may not be able to tighten the cranks properly. I can imagine other brands of bottom bracket may give you more room to tighten the crank, if they fit closer into the BB shell.

I have a Tiagra FD on this and another bike with a Spa XD-2. In both cases it shifts very well, and I do have it a bit high on the XD-2 bike - not as much as 10mm though.

PeterH

[slowster]

It looks to me like you will need to get a braze on front derailleur. You can then use the type of adapter which has a slot, which I think (but cannot guarantee - you'll just have to try it) should give you the necesary range of adjustment to fit the derailleur at the right height without the adapter fouling on the bottle boss.

Regarding cutting the steerer, if this bike is quite different from your current/previous bikes (not least in the position you might want to adopt/experiment with, e.g. possibly a bit more upright, possibly a shorter stem than you usually use, different bars etc.), then you might want to consider not cutting much or even any of the steerer until you have had the bike for a while.

If so, you just need a lot of spacers and probably an extra star fangled nut, so that when you eventually decide to trim the steerer down, you cut off the surplus length with the star fangled nut inside it. Alternatively you could use a bung like those supplied for carbon steerers, which can simply be removed when you decide to cut the steerer (they are usually a looser fit in a steel steerer with its wider internal diameter, but I find I can stop them just spinning around by tightening them first to expand them a bit before inserting them).

As for the BB length and chainline, I guess something has to give when combining road chainsets with very wide chainstays. At least with square taper chainsets you can use bottom brackets with different axle lengths, and you can buy a 118mm UN55 for not a lot of money.

[mattsccm]

Cutting a steering tube apparently really does need snake oil or so you would think going by the internet. In practice you just chop it off in the right place. I did a carbon one with a bread knife. It doesn't even need to be perfectly level as long as it allows the bung to fit and not foul the top cap.

[reohn2]

Slowster
IME on my Vagabond the limiting factor of lowering a front road mech is the cage tail coming in contact with the chainstay,MTB mechs with a low band fitting have the pivots,etc behind the seatube which are in the way of fitting mudguards if using the bike's potential for 2.1inch tyres.
Though as I mentioned in my previous post(see photo)a road front mech with 10mm clearance above the chainring(similar to the OP's photo)works beautifully

[geomannie]

Hi Everyone,

Your replies are really appreciated. I am getting a better understanding of what I might need to do.

I have carefully checked the chainline & it is 45mm front & rear. However, I feel that the ~1mm clearance between the inner 24T and the chainstay is too close for comfort. I have never had to think about chainlines before so for the avoidance of doubt, if I replace the 113mm BB with a 118mm BB this will move the chainset out by 2.5mm? ((118-113)/2). Is the general opinion that have the chainset 2.5mm out of alignment OK? I note that the cassette is 35mm thick so each gear (9 speed) is about 4.4mm apart so intuitively I see no great problems.

This leaves the Sora FD possibly too close to the tyre. I have managed to adjust it out a little bit using the lower limit screw but it remains a bit close for my liking (Maybe its OK & I worry too much?). I have measured the length of the Sora mech and compared it to others I own. Most seem to be in the range 110-115mm. The Sora is 120mm. A shorter mech should help. reohn2, could you possibly measure the length of your Ultegra FD6603 for me? I can't find the dimension online.

Thanks also very much for the heads-up on steerer tube cutting. I have an itchy new hacksaw blade waiing.

Cheers

B

[slowster]

if I replace the 113mm BB with a 118mm BB this will move the chainset out by 2.5mm? ((118-113)/2)

Brucey measured the dimensions of various UN55 BBs a while ago, and nsew provided the values for the 113mm BB, here. According to their measurements, the RH stickout of the 118mm is 2.1mm more than the 113mm (25.6mm - 23.5mm).

[reohn2]

Hi Everyone,

Your replies are really appreciated. I am getting a better understanding of what I might need to do.

I have carefully checked the chainline & it is 45mm front & rear. However, I feel that the ~1mm clearance between the inner 24T and the chainstay is too close for comfort. I have never had to think about chainlines before so for the avoidance of doubt, if I replace the 113mm BB with a 118mm BB this will move the chainset out by 2.5mm? ((118-113)/2). Is the general opinion that have the chainset 2.5mm out of alignment OK? I note that the cassette is 35mm thick so each gear (9 speed) is about 4.4mm apart so intuitively I see no great problems.

This leaves the Sora FD possibly too close to the tyre. I have managed to adjust it out a little bit using the lower limit screw but it remains a bit close for my liking (Maybe its OK & I worry too much?). I have measured the length of the Sora mech and compared it to others I own. Most seem to be in the range 110-115mm. The Sora is 120mm. A shorter mech should help.

Thanks also very much for the heads-up on steerer tube cutting. I have an itchy new hacksaw blade waiing.

Cheers

B

A 118mm BB will push out the chainset a minimum of 2.1mm away from the chainstay so 1mm clearance becomes 3.1mm.
This also pushes the front mech by the same amount so helping with clearance between inner cage plate and tyre.
But unless you've run the chain through the mech and adjusted it accordingly you won't know how much further the inner limit screw needs adjustment outwards.

reohn2, could you possibly measure the length of your Ultegra FD6603 for me? I can't find the dimension online

Which dimension ?
Do you mean total length of the cage plate?
If so outer or inner?
Theres also seatstay to chainstay angle to consider ie; a more acute angle may mean a shorter cage plate intended for a larger inner ring.
I have a few mechs road and MTB in 'the box' I can measure,but if you intend using road STI's they won't shift MTB mechs far enough over three rings,friction will do any combination and 9sp MTB pods surprisingly work great with both Tiagra and Ultegra mechs I've tried them with.

EDIT:- all that said if your chainline(centre of middle ring to frame centre)is 45mm,a 50mm chainline(like mine)will need an even longer BB,a 121mm(mine is that length)

[fatboy]

.......Yes you need a gap, the top cap needs to be pressing on the stem or spacer and not bottom out on the steerer. I leave a 10mm spacer above the stem, just for a bit of future adjustability.

Yep,spot on
I forgot to answer that bit

I'm a fan of not cutting down fork steerers at all. Any bike that I've had with a neatly cut down stem has been too short for me! Also I'm only going to need higher bars as I get older so I plan ahead. Everyone who notices this tells me I should have cut it off to which I shrug and ignore them

[slowster]

It might be worth taking a step back at this stage and reviewing your transmission and gearing choice, and considering what other alternative options might give the same gear range and intervals. People might be able to provide better advice if they knew what the planned set up will be, i.e.

- Will it be 9 speed or 10 speed?
- What cassette?
- What shifters?
- What rear derailleur?

Possible options I think I would probably be considering would include:

1. Instead of a 118mm BB, fit a 122mm instead. That will increase the chainline by 5.1mm (28.6mm - 23.5mm), i.e. giving the standard Shimano MTB chainline of 50mm. After all the complete Vagabond bike is fitted with an MTB chainset and derailleurs (I don't think the frame was designed with the expectation that it would be fitted with a road chainset and front derailleur and a 45mm road chainline). I suspect you would need an MTB triple front derailleur, assuming that the Sora road triple could not cope with the required extra 5mm of throw, which in turn might not be compatible with your current choice of shifter.

2. Fit a super compact double and a front derailleur for a double chainset instead. Spa's standard super compact with a 24t inner has a 40t larger ring plus a chainguard. The 16t difference is what most Shimano double front derailleurs are designed for, although I suspect 42/24 might work OK. Since you've already got the triple chainset, you would need a 40t or 42t ring plus a chainguard to convert it to a Spa super compact. Spa recommend a 116mm BB with their super compact, so the most appropriate UN55 would be the 118mm.

One reason why I suggest this, is that to me a 46t outer seems large for a bike like the Vagabond. I guess it depends upon your fitness, whether you are a gear masher rather than spinner, the terrain you ride and how much is off road, and the overall weight of bike and kit, but Genesis themselves supply the complete bike with a 40/28 chainset and 11-36 cassette.

3. Fit an MTB triple like reohn2, with 42/32/22 chainrings, which might be a better option if your most used ratios would be the 32t with the middle sprockets in the cassette (as opposed, say, to finding that with a 40/24 super compact that you tend to cross chain and often use the 40t with the big sprockets). However, again I suspect you would need an MTB triple front derailleur, which might not be compatible with your current choice of shifter.

As you say, it's almost inevitable that you will hit wrinkles and issues like this when building such a bike. When that happens to me, I usually try to identify all the possible alternative options with their pros and cons, and then sleep on it for a few days or even a week or more. Whereas when I initially encounter such problems they can leave me very frustrated and annoyed, I usually find after a few days I have a much better perspective on the problem and what is the best solution.

[reohn2]

I've been giving the timeline and changes to my Vagabond build a coat of thinkology.
Initially I built it up with a compact double of 24/39t Stronglight Impact triple(same as the Spa TD) chainset using the two inner ring settings with a bashguard in place of the outer.
The build used a 121.5 or 122mm UN55 BB with the Ultgra front mech with drops and a friction shifter,I then swapped the 'bars for PX Geoffs and Deore MTB 9sp shifters .
Then I thought I'd try an MTB triple chainset(the one in the photo up thread)and without altering anything but a tweek of the limit screws everything worked like clockwork.
I strongly suspect a 121.5/122mm UN55 will sove the OP's problems with the Sora mech he has fitted.