Isen workshop: adventures in batch production (or not...)

In fairness to isen, the spec for the first gen was 35mm in 700c. Challenge tyres tend to come out a bit wider and with nobbles “33mm” is prob about 35.

my isens been great. 2 years no problems at all. No one asked - but just thought i'd share.

p.s - first batch of isens imo are not gravel bikes. stick some road tyres in there and go for a ride. Have fun. Repeat.

Same sentiment here. I find it is more of an all season road-bike with generous road clearances rather than gravel bike. The Columbus Futura Gravel fork is not that generous with clearances either and in my opinion not really a gravel fork.

Only issue with my gen1 is that the dropouts are a couple mm narrower than 135mm so a pain getting rear wheel in and out.

Only issue with my gen1 is that the dropouts are a couple mm narrower than 135mm so a pain getting rear wheel in and out.

I have this problem as well. I fixed this in a totally non agricultural way at all, gently prizing the two chainstays apart and its been fine.

Yeah Kat loved riding her bike on the road before the crash. When we were deciding whether to get another Isen as the replacement or look elsewhere it was the fact that the 51cm frame had recently been redesigned with bigger clearances and specifically for 650b wheels (previously was 650c and 26inch) that clinched it. The bike needs to serve both long days in the saddle on the road but also gravel and bike packing.

Clearance for 42c plus guards seemed the ideal amount for the bikes intended uses....

Clearance for 42c plus guards seemed the ideal amount for the bikes intended uses..

Ee, when I were a lad rough stuff tourist's got one and a quarter (that's 32mm in the new money) if they were lucky. You whippersnappers are spoiled...

There's something off with the marketing copy on the site, it states up to 40c in the intial text, and then '42c with mudguards (measured)' in the next section.

The 42c with mudguards must be an error, and 40c without mudguards the max?

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Yes, agreed - in fairness to Matt.
My first gen Isen has had some annoyances but in general it rides wonderfully. I’ve racked up 10,000k on it!

As a road cruising machine with 28mm rubber it is smooth and fast. With guards, I ride it all winter on the road.

I find it just fine for my gravel riding (Danish forests, mostly hard pack fire road type surfaces) with 33s.

My chain stay clearance is such that it will just take a Challenge Grifo 33, but can’t accommodate a Challenge Chicane 33.

Here it is this evening in gravel mode.

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Managed to get hold of the bike, and although im going to need to confirm tomorrow morning im pretty sure ive got to the bottom of it, and as usual its pretty much what tester said.

I put wheel in with the 42c tyre, and as @Saffronspokes had the displeasure of discovering it was indeed very much in contact with the frame. Next step was to check alignment of rear end on surface plate using BB face as datum, everything ok. I then put dummy wheel in with nominal 650bx42 tyre, and everything was ok there too. Next step was to put new stock wheel without tyre in, which was centred. Ive attached photos of the dummy wheel on surface plate for people as dull as me who find this stuff interesting.

After waving a vernier at the wtb tyre, it appeared to be not only width wise oversized, but also very tall, even without taking knobbles into consideration. This causes us issues as after the tyre the stays need to bend in very aggressively to clear the road q factor cranks/road chain line, so if the tyre goes beyond where we expected it to be, it very quickly gets boxed in by chainstays darting inwards, away from the cranks.

On their own these issues wouldn't be enough to cause any grief, but together they compound very quickly to what sam bumped up against this weekend.

Nomimal clearance and real world clearance often dont have a lot in common, just compare the nominal 42c tyre guide in the picture attached versus Sam's photos and you'll see what i mean. He was sold a bike that said it cleared a 42c tyre, bought a 42c tyre and somehow found himself with a new permanent braking system instead of fashionable mixed terrain rubber attached to a boutique artisan frame.

We have actually put a whole section on our (soon to go live)new website about this exact problem, and are looking at ways of mechanically squeezing a little more room if we can, but while narrow cranks, short stays and fat tyres are being used its always going to be a squeeze.

Once im sure that this is the issue, im going to increase dimple size to match these tyres, and going forward im going to change dimpling process to move the dimple centre slightly further up to avoid this from happening in the future.

Im also going to post some parts of a (unused) check list to show how many times we check rear end alignment throughout the build process. This isn't for any defensive reasons, but solely so that everyone who had clearance issues with the protoype frames knows we took that incredibly seriously and put a lot of checks in place to avoid it happening again.

@Saffronspokes ive dropped a message on email, and will be sending proper report tomorrow, thanks again for spotting this. We sell a lot of frames abroad now so incredibly grateful this didnt happen in Malaysia! 😂

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And a little collage of everyones favourite thing, paperwork! Little pink lines are where CS clearance is checked.

Will update tomorrow with photos of frame with proper clearances, and more things with height gauges and verniers for those dull enough.

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Thanks @coldharbour we got the email and really appreciate you looking at it so quickly and replying well out of 'work hours'. Really glad that hopefully you can sort it out for Kat.

One thing it would really help to clarify is the '+ guards statement' on the website. The fact the frame is noted to have room for 42 plus guards is probably where quite a lot of our issues came from. It would imply that there should be ample space for a 42c tyre even if it comes up bigger as guard clearances are quite a bit. Anyway, in our case if it's fits 42 without guards that will be just fine. Thanks again for the swift action and hopefully it'll all be sorted this week!

Not a problem at all, we had a lot of practice dealing with clearance issues early on so this was just revision for us 😂.

Ill post a pick tomorrow with a pdw guard in place so you can see where it would go, but of you imagine the there being an offset profile following the leading edge of the tyre guide in my post above, which would come right up to the stays in this set up.

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https://blog.3t.bike/2020/06/14545/gravel-tire-dimensions-explained/

Good work on a quick response and clear explanation of the issue. Glad to see that you have developed some QA routines.

Just thought I would post some photos from last week of clearances with various wheels for those interested. We managed to get some reasonable clearance with the oversized WTB, and oodles with the gravel king.

We also fitted a set of wheels with a true to size compass (rene hearse) knobbly, which as you would expect had more than expected from spec. clearance.

Main take home from this I think is that there is very little room to play with on modern high volume gravel/road bikes around the BB, and a number of small variances in parts can combine to create far bigger issues.

Thanks again to the owner and @Saffronspokes for letting us work it out with them, and personally glad we could sort it out without any drama. Will also post when new website goes live with the info page relating to this very topic, as it is something we are going to all be working with for the foreseeable future!

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Thanks @coldharbour hopefully many thousands of on and off road miles lie in store for the bike. Appreciate the pro-active and timely manner in which this was all sorted.

So, the solution is buying expensive tires!
No surprise there.
Nice handling if the situation and good info also.

On what rims? Are they true? Where are your measurements?

So your wheels (presumably) weren't dished correctly, and your tyre was significantly oversized. Do I get a prize?

What did they even sort? If they re-clearanced the frame (I would guess involving at the very least touching up the paint) to take your non-spec tyres, for free, that's remarkably generous after the way you've handled this.

Nice to see all the apologies from everyone for the pile-on though.

Oh, wait.

I commended them on fast response and for having developed qc processes.

They dimpled the frame in the correct place and with more pronounced dimples. There is no way that the original frame would have taken 42c (true to size) plus guards.

Anyway, it's sorted now and we're appreciative of their help. I'm not quite sure what your angle is and why you are being so confrontational about it. I fail to see how I handled it inappropriately, If anything I think the above is really good for Isen. It shows how they've developed new processes and how quickly and seriously they sorted the issue. This should give people confidence that by buying from a small business you will be looked after.

I think we have responsibility as an industry here, as at the moment it is just a wild west of numbers that should work together and dont. We should have more info on the website (and will do soon) explaining this, i dont think that sam did anything wrong at all, if anything this hss been a really useful demonstration of issues you can encounter with the collection of parts.

You are an actual Saint.

.

Good to see @coldharbour being proactive and timely there. Glad it's sorted @Saffronspokes.

GCN feature, you is famous-ish

https://www.instagram.com/p/CPA1qBxMhfR/?utm_source=ig_web_copy_link