M_V's multitude of bikes and adventures in the land of framebuilding

Now building a bike around a set of bottle bosses or a cable stop..

Haha no offence taken. It is a bit much but then that yoke is so lovely. It’s worth building a bike around!

Konga yoke is on the way so ordered up some more stuff to build frame no 002.

I’ve decided to use a set of chainstays and socket style vertical dropouts that I brazed up as a practice exercise early on and use an eccentric bb to do the chain tensioning. Didn’t realise the Bushnell inserts were so expensive but they seem to be the best way to do an ebb.

Mech hanger has been chopped off the drive side dropout.

Using vertical dropouts means I can add a single mounting point to the underside of the non-drive chain stays for the coaster brake torque arm. Should be more reliable and neater than a slotted mount.

The top and downtubes will be 31.8mm Thron tubes, the seattube will be externally butted Zona. 1 1/8” headtube with a suitably beefy 1.6mm wall, also from the Thron set.

I’ll do segmented seat stays again I think.

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My chainstays and there’s an event on at work so not much for me to do so started on a couple stems...

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Stem is coming along.

Tubes came in from Ceeway yesterday and the yoke from @Konga yesterday.

Yoke is so rad, can’t wait to build with it.

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Nice. So some kind of MTB right?
29"? 27.5"? 26"? Sus or not?

Yeah mtb.

67.5er I think as in 26” rear and 27.5” front.

I have the wheels already, they used to be on the Hummus.

I’d maybe have gone 27.5” both ends but the coaster hub is 36h and there’s not many 27.5” rims in 36h flavour.

WTB make the Ranger in 26x2.8” and it’s not silly expensive so probably get one of them to fill up the yoke.

I've got a 36h 27.5" rim being built on a coaster hub (my spokes are 1 or 2 mm too long, need to sort that out). There's a few about although nothing especially fancy, I think mine is Mavic but there's no stickers

e.g.

https://shop.mavic.com/en-fi/ex-630-disc-j33100.html#1028=3283&1035=3806&1039=3515

https://www.halowheels.com/shop/components/rims/sas-27-5-rim/

When did you order the yoke dude?

Emailed Antii a couple weeks ago.

Canny wait to get this thing built!

I could just swipe the HT2 cranks off the Surly for this but thought something a bit more old school was in order so put in an offer on these Coda cranks on eBay today and it was accepted.

They’re not the Tarantulas I’d really like but they cost me bugger all so...

Think I’ll pick up a stainless Surly ring to go with them.

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Interesting. I paid him over a month ago and still nothing

Got the brazing on the quill stem finished off today.

Brass rod is in, just need to visit my dad to use his lathe to turn up a cap for the bolt to sit in and then cut the requisite angle in the quill part and it’ll be good to go.

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Trying to figure out geometry for the next frame.

The Hummus rode nicely as a klunker so I was going to just copy it but I want to use a 1x1 fork I have (shorter than the orange fork on the Hummus) and upon measuring the frame and comparing it to the geo charts for some other frames, it’s actually really quite short and slack (69deg seat tube, 65deg headtube, think the ‘actual’ toptube was around 56cm).

So I think I’m going to steepen the seattube to 70deg, the headtube to 74deg (which is what the Surly Lowside is) and stretch it out a little too.

In order to use the 1x1 fork I’ll have to keep the headtube pretty short at around 110mm but I plan to use the big motocross bars on it so that should keep the front end plenty high enough.

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seattube to 70deg, the headtube to 74deg

Sounds like a silly looking bike haha. Im guessing the angles in the drawing are the right way around ;)

Edit: rad plan btw. Maybe it wont be necessary due to moto bars, but couldn't you lengthen the fork steerer if the front end is too low?

Oops, yeah 70 head and 74 seat angles.

Remeasured the Hummus and the effective tt is than I thought at 595mm. That still places it between the S and M Lowsides though. Actual tt is 565mm which is only 3mm longer than the XS Lowside!

Reach on the Hummus is just a shade over 400mm.

If I stretch the effective tt out to 620mm (between M and L on the Lowside) it'll give me an actual tt of just a hair off 600mm but because of the short headtube the reach would be 470mm which is considerably more than the Hummus but it is between L and XL on the Lowside which might not be too bad since I am 6'2 a lot of which I think is in my upper body.

I could lengthen the steerer, I've plugged and sleeved handlebars before with my stick welder but I think really for a steerer it'd want tig welding (and cleaning up on a lathe).

I reckon with the moto bars it might be ok as is though and actually, I had about 20mm of spacers under the stem when I had the fork I'll be using on my 1x1 frame (110mm headtube) so I can probably gain a bit of headtube length by running no spacers. The bars won't move but I don't think they need to and it'd make the reach figure a bit more...'normal'.

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It's only when you add the '.0' onto things that you realise what Surly were up to when they specced a 413mm a2c on the 1x1 fork...

413.0mm, 4130 chromoly steel.

Got the cap turned for the quill stem...

Fitted photos in a mo.

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Fits nicely.

Hoping for some dry weather either tomorrow or Monday so I can test ride it.

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That is a very lovely thing indeed.

The headset cap in particular is wonderful. You could sell a bucket load of those I’m sure, if you had the inclination.

Thanks.

I need to work on accuracy and repeatability because it’s pure luck that angle worked out.

Think I’m gonna try a 31.8mm clamp one next.

That’s the bit about frame building in general that always blows my mind is the measuring and mitring all the tubes and angles etc. I have no idea how you go about achieving that level of accuracy, although I guess with things like bikecad etc a lot of it can be worked out in advance, but I imagine - like many trades - the craftsmanship comes with repeat experience that no amount of computer help can replicate.

Yeah, it’s the designing and planning part that I struggle with the most.

Luckily, with the frame I’m about to start I had to order a different seattube (originally bought an externally butted one then realised that won’t work very well with that reinforcement plate design I used on the tt/st junction on the last frame) and I’m still waiting for it to arrive so planning and designing is all I can do right now.

I think I tend to work in quite an organic way anyway, preferring to just get stuck in over spending time planning all the details and it has definitely been my undoing in the past.

Definitely think your right about repeat experience though and I think that’s why buying the torch and stuff and just making stuff was the right way for me to learn. I think I’ve a couple more frames and a pile of stems to go before I’ll have spend as much as I would have on travelling to the other end of the country and doing a framebuilding course which would only have seen me build a single frame.

Yeh you can’t beat learning by doing.

And re: the frame course, the general consensus seems to be doing one frame building course won’t make you a ‘frame builder’ it’s just a nice way to be able to build yourself a frame in a controlled environment with the guarantee that you won’t be allowed to balls it up.