Solve my unbalanced bike issue *No Reward*

[sam]

*Title is a reference to this post, which incidentally led to my getting to meet LittleWheelsandBig.

I've got a Sabbath Aspire which doesn't care to be ridden no-handed. It favours the right side of the road, leading me to wonder if it's also half American.^[1] I've christened it Wayward Child.

While this probably wouldn't be an issue for most, it is for me, as it detracts from my pleasure in taking it out. Fortunately I've got a twin Aspire (not to brag - it's about the cheapest ti available) which has no such issue, but I'd really like to solve this at some point.

It's been like this from the start, circa January 2023. I built it up using both new and old parts, one of the new parts being a headset (the cups having been installed by the shop), an older part being the rear wheel. I mention those because I figure either could be implicated. I really don't want to contemplate a frame issue, because there's nothing I can do about that. It's not like it's going to end up on eBay.^[2]

I'm pretty sure I've swapped out the wheel for a confirmed good one, which I should really double-check, but meanwhile, any ideas? I'm even considering some sort of bodge to ever-so-slightly raise the right side of the rear axle, if such is possible.

The only reward for a successful solution I can offer is a guided tour^[3] of my neck of the woods.




1. Born over there, not exactly dragged over here. Acquired British citizenship some time ago. Have now lived approximately half my life here, with no plans to return – even for a visit {shakes fist at Covid}. But of course, I can never be truly British. I don't drink, for a start.

2. Shameless link to a GENERIC frame, language gently suggested by my lawyer.

3. No expenses paid, though I'd be happy to cover your tab at the Bear Inn provided it doesn't run into double figures.

[rogerzilla]

There are two usual reasons for a bike being difficult to ride hands-off:

1. Too much* fork offset for the head angle.  This can be addressed by fitting a fork with less offset.  Finding out what the existing offset is can be a challenge.  Try the original retailer as it is a hard thing to measure directly.  If it's already 43mm, typical for a road racing bike, there's not much you can do.  If it's at least 48mm, fitting a 43mm offset fork will noticeably increase the self-steering effect.  I can't find an offset quoted for the Aspire but the Silk Road seems to be 50mm with a 73 deg head angle, which is definitely into twitchy territory.

2  Tight headset or badly-faced head tube and fork, causing binding.  More common than you might think.  Does the fork rotate smoothly through a full 180 degrees without the wheel fitted (this adds momentum and makes it feel smoother than it is)?

*Handling preferences and needs vary and anything designed to carry luggage will have less self-steer.

[sam]

Thank you kindly for the lines of inquiry. I'll look into these things. Re too much fork offset, this bike's twin uses the same fork with no problem.

These are a bit twitchy, but I've compensated



and now manage fine on the other one, though the handsfree experience could be more relaxing.

[LittleWheelsandBig]

If you walk the bike through a puddle in a dead straight line, are there two tyre tracks or one?

[sojournermike]

Fork offset on the Aspire is almost certainly 45mm - in line with the other Sabbaths and most of Spa’s bikes (ignoring the 60mm offset forks for some of the  slacker stuff)

Also consider if the cabling is introducing some ghost steer?

Amazed you haven’t sold that art piece/frame yet - seems a bargain compared to a Banksy or a Hirst

If the frame hails from Kansas you call it ‘My Wayward Son’ and Carry On knowing there’ll be peace…

[mzjo]

I don't know much about riding no hands, being incapable of doing it on any bike even though it would be useful sometimes (aching wrists and the like). However this bike is steering up the camber and side-carring experience would suggest that the front tyre might be touching the road more on the right side than on the left (an effect likely to be accentuated the wider the tyre and the flatter the tread). It wouldn't need to be much if the bike is already sensitive to steering issues. (On an outfit this effect can be created deliberately by adjusting the bike to lean out to help it go in a straight line and the effect is also a bit speed dependant; on a two-wheeler this won't be so evident because you lean the bike to steer it).
Nb: I am not saying this is what the problem is. If you have already had to change the front tyre and the behaviour is just the same then it probably isn't. I am also not suggesting that you swop front wheels between bikes, leave the good one well alone! But turning the tyre on the wheel should change the bike's behaviour (not necessarily for the better) if this has anything to do with the problem (or changing tyre completely of course).

[Paul H]

I've no idea, but with two identical framesets I'd suggest swap testing is the way to go. One component at a time, or multiples and swapping back, without those pesky gears it's all straightforward.

[sam]

If you walk the bike through a puddle in a dead straight line, are there two tyre tracks or one?

Are you asking me to get my titanium bike wet? I'll have to get back to you on that.



Looks like a rain dance is in order to hurry that along, which may disappoint other cyclists.

Also consider if the cabling is introducing some ghost steer?

Think I've checked, though it doesn't hurt to check again. Slightly easier because this is a SS – were it a FG, might be easier yet ("Look ma, no brakes").

As to the art that's for sale, I heartily agree.

(click to show/hide)

Every once in a while someone will get in touch, almost always offering a version of 'Chapeau!' (the last message was literally that), but I have had some incredulity. Believe it or not.

If the frame hails from Kansas you call it ‘My Wayward Son’ and Carry On knowing there’ll be peace…

Chapeau. This song also comes to mind.

Not to go too far off topic,* but speaking of the great Midwest:



(Link for context. Tina's recent death adds poignancy.)

I am also not suggesting that you swop front wheels between bikes, leave the good one well alone!

with two identical framesets I'd suggest swap testing is the way to go. One component at a time…

Although one of the reasons I got twins (wife: "How do you tell them apart?" me, shocked she'd even have to ask: "The stem is set 10mm lower!") was precisely to make troubleshooting easier, as well as have the option to run wildly different components (to ruin the previous joke, the stem on one is titanium, and the cranks are black instead of silver – which tbh still wouldn't help her tell them apart), it turns out I am indeed loathe to mess with a well running bike, that being another reason for doing this: to increase the chances of always having one that's not currently giving me trouble.

However, swapping front wheels, and just reversing the one already on there, are so easy that it's one of the first things I did, to no effect. As mentioned, I think I've swapped rear wheels as well. 23mm & kept fully inflated, btw. Back to @rogerzilla, the fork does rotate smoothly, but I'd not thought to check that w/o the wheel loaded, which I'll try. Funnily enough the twin's isn't nearly as smooth! Which of course bugged me, and now bugs me more considering the possibility that it may have a badly faced headtube/fork (I've made sure it's not too tight), but in this case even though it may technically be 'broke', I probably wouldn't be fixing it.



* I'm a fan of rabbit holes - the good kind.

[sam]

Just went out for a short spin to the train station to practice in the parking lot and possibly show how it's pulling to the right. My plan was to video the event. Which I did.

(click to show/hide)

It's hardly worth the time it'll take to click over to YouTube. Though I did score and subtitle it.

It turns out I don't like holding a camera whilst attempting to ride no-handed on a bumpy surface with uneven lighting. Go figure.

[LittleWheelsandBig]

Sight along the side of the rear wheel/tyre and compare it with the angle/ position of the front wheel/ tyre. It should be fairly easy to see if they are not parallel. The front wheel might be inclined vertically or offset horizontally from the rear wheel. If the wheels are exactly in line, then I would be looking for a possible rear brake cable influence or a headset issue.

[The Family Cyclist]

Have you asked someone not aware of the problem to have a  ride to see if they feel it?

[sam]

Sight along the side of the rear wheel/tyre and compare it with the angle/ position of the front wheel/ tyre. It should be fairly easy to see if they are not parallel.

You'd think.

The front wheel might be inclined vertically

Are you saying it's OK if I happen to test this on an incline? Otherwise this bit isn't computing for me, sorry!

or offset horizontally from the rear wheel. If the wheels are exactly in line,

It's actually not that easy to see if they're exactly in line, or at least wasn't for me – what with the seatpost in the way, and the necessity to ensure the front wheel is exactly dead ahead. As far as I could tell both bikes were either fine, or off.

then I would be looking for a possible rear brake cable influence or a headset issue.

Both bikes are set up similarly enough to make the cable possibility unlikely, but I will do the necessary to cross that off the list.

As for a headset issue, is it possible to have the bars turn smoothly yet still have headset problems?

Have you asked someone not aware of the problem to have a  ride to see if they feel it?

I have no other warm bodies to throw at the problem.

[LittleWheelsandBig]

Look along the side of wheels below the axles. Bike upright, wheels in line, crouch down behind the bike and peer level with ground below the bottom bracket. See if one wheel is inclined compared to the other and see if the front wheel is consistently one side of the the rear wheel.

[sam]

That's exactly what I was doing 10 minutes ago. I'll check again...

[LittleWheelsandBig]

It can be useful to position the bike in a gutter with a straight curbstone. A yardstick laid against the rear wheel would be best.

[Blodwyn Pig]

As LWAB says, if you look at the rear tyre , square on from behind, you shouldn’t see any of the front tyre at all.

[sam]

I just took it out with the rear brake cable disconnected.


Hurry up and cross me off the list. ✔

When that didn't do the trick I adjusted the front wheel so the axle was ever so slightly unseated on the right. Bingo. Suddenly fine sans hands.

[LittleWheelsandBig]

Sounds like the fork may not be holding the front wheel in correct alignment.

Have you tried reversing the front wheel within the fork?

[sam]

Have you tried reversing the front wheel within the fork?

Yes. That had no effect.

[mzjo]

Fork ends not aligned correctly for height? Try repeating the operation with the wheel the other way round, or with another wheel to confirm (or not)?

[Blodwyn Pig]

Dremel time!

[LittleWheelsandBig]

A rat-tail file to the top of a dropout sounds like the go.

[sam]

Is it possible the frame is slightly off (even though I can't see anything wrong with it), and my little stunt with the fork is correcting it? Or does this confirm the fork is definitely the culprit? Which would be as close as I'd get to a happy ending here.

I'm not particularly keen to start an arms race, as it were, between fork ends should I file it wrong the first time. Provided my 'repair' holds, i.e., the Q/R is tight enough not to slip down, I'd just as soon go with that. Unless I'm reliably informed that'll make my bike explode à la The Simpsons.

Also, how common do your reckon it is that forks are {slightly} frakked in this way?

[sg37409]

If you walk the bike through a puddle in a dead straight line, are there two tyre tracks or one?

Oh, thats a good way of checking that.  Mental note...

[LittleWheelsandBig]

It is possible that the frame is a touch out of track and skewing the wheel in the fork is compensating for it. Does that actually matter if it gives the result you want?

Both frames and forks have construction tolerances. Either or both could be out a little. Welded frames move alignment a little as the welds cool down. Straightening a Ti frame takes quite a bit of cold setting but it can be done. I guess you have a bonded fork. It isn't unknown for the fork components to not be fully seated in the jig while being bonded.

You can leave the front wheel slightly skewed in the fork without major dramas.