Look 795 Blade

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markyboy
Posts: 1123
Joined: Wed Dec 29, 2010 10:22 pm
Location: Bristol uk

by markyboy

Do you need to use the look stem or will any other stem work as my frame came with no stem so I have to source one and it's 6 weeks wait
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by Weenie


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rudye9mr
Posts: 498
Joined: Wed May 01, 2019 12:01 pm

by rudye9mr

The front fork is square/rectangular rather than round so you would need LOOK's stem....also ensures 'perfect' alignment between stem and fork

SLH
Posts: 82
Joined: Wed Nov 18, 2009 12:07 pm

by SLH

markyboy wrote:
Wed Jun 23, 2021 5:14 pm
Do you need to use the look stem or will any other stem work as my frame came with no stem so I have to source one and it's 6 weeks wait
This seems weird that you don't have the stem. Wasn't it a part of the original order?
Look 795 Blade RS
Sram Red AXS
DT Swiss ARC 1100 Dicut 50

Defender110
Posts: 26
Joined: Mon Mar 09, 2020 11:21 pm

by Defender110

markyboy wrote:
Wed Jun 23, 2021 5:14 pm
Do you need to use the look stem or will any other stem work as my frame came with no stem so I have to source one and it's 6 weeks wait
I've got an extra 110mm stem if thats what you were looking for - some spacers also - let me know if you want it - I can ship (probably takes a few days to get to UK since I'm in EastCoast US).

markyboy
Posts: 1123
Joined: Wed Dec 29, 2010 10:22 pm
Location: Bristol uk

by markyboy

Defender110 wrote:
Thu Jun 24, 2021 1:41 am
markyboy wrote:
Wed Jun 23, 2021 5:14 pm
Do you need to use the look stem or will any other stem work as my frame came with no stem so I have to source one and it's 6 weeks wait
I've got an extra 110mm stem if thats what you were looking for - some spacers also - let me know if you want it - I can ship (probably takes a few days to get to UK since I'm in EastCoast US).
Perfect I will buy it how much is it ?
Colnago arabesque campagnolo super record 12
Colnago c64
Cinelli zydeco grx di2

kieler2020
Posts: 15
Joined: Mon Jun 15, 2020 12:40 pm

by kieler2020

So, to add my 2 cents worth to the discussion about loosening headsets, it seems like I've maybe found whats causing my problem. A few months ago I readjusted for a better fit and cut the steerer tube and since then it has always started loosening up. I've tried everything (carbon paste etc.) and it alwas came back after a few hundred kms. It never made sense because the expander, although crap and poorly fitting, wasn't pulling up even under 12Nm tension. On a whim today I tried to fit a feeler gauge in between the flat face of the steerer and the stem whilst still installed (at 5Nm). And what do you know? I can slide a 0.1 mm gauge right down both sides :shock: See photo (in case you're wondering, I use the Look supplied spacer under the top cap).

It turns out that either the front part of the steerer is very slightly narrower than the rear, or the stem itself is a asymmetrical. Since the stem is clearly designed so that most of the clamping surface area is on the two flat sides, my stem is only making contact towards the back half of the steerer tube (the front doesn't count as the stem is hollowed out there). So of course it will never hold tight.

I'm sending this to Look for a hopefully helpful response...

S
Attachments
20210624_124354.jpg

Defender110
Posts: 26
Joined: Mon Mar 09, 2020 11:21 pm

by Defender110

markyboy wrote:
Thu Jun 24, 2021 4:20 am
Defender110 wrote:
Thu Jun 24, 2021 1:41 am
markyboy wrote:
Wed Jun 23, 2021 5:14 pm
Do you need to use the look stem or will any other stem work as my frame came with no stem so I have to source one and it's 6 weeks wait
I've got an extra 110mm stem if thats what you were looking for - some spacers also - let me know if you want it - I can ship (probably takes a few days to get to UK since I'm in EastCoast US).
Perfect I will buy it how much is it ?
Email sent.

achin
Posts: 37
Joined: Sat Jul 04, 2020 4:41 pm

by achin

kieler2020 wrote:
Thu Jun 24, 2021 12:19 pm
So, to add my 2 cents worth to the discussion about loosening headsets, it seems like I've maybe found whats causing my problem. A few months ago I readjusted for a better fit and cut the steerer tube and since then it has always started loosening up. I've tried everything (carbon paste etc.) and it alwas came back after a few hundred kms. It never made sense because the expander, although crap and poorly fitting, wasn't pulling up even under 12Nm tension. On a whim today I tried to fit a feeler gauge in between the flat face of the steerer and the stem whilst still installed (at 5Nm). And what do you know? I can slide a 0.1 mm gauge right down both sides :shock: See photo (in case you're wondering, I use the Look supplied spacer under the top cap).

It turns out that either the front part of the steerer is very slightly narrower than the rear, or the stem itself is a asymmetrical. Since the stem is clearly designed so that most of the clamping surface area is on the two flat sides, my stem is only making contact towards the back half of the steerer tube (the front doesn't count as the stem is hollowed out there). So of course it will never hold tight.

I'm sending this to Look for a hopefully helpful response...

S
From my experience, you actually would likely have the clamping occuring on the front and rear curved section of the stem and not the flat sides. When you put the expander plug in, you should see some expansion of the tube occuring where the expander plug is pushing against. Match that with the 2 bolts on the stem, and you should see a tightening occur at the front and rear of the steerer.

Have you tried tightening the bolts on the stem first a bit, then the expander plug to spec, and then lastly tighten the stem bolts to spec? The problem with the design IMO is that with how it is arranged, you either tighten the expander plug first, or you tighten the stem bolts first. If you tighten the stem bolts too much, you cant fit the expander plug down the hole, as tightening either will affect the steerer tube dimensions (expander plug will expand then steerer tube, while the stem bolts will contract against the stem tube...) so which do you do first? Technically by tightening one, you actually affect the torque settings of the other.

I typically tighten my expander to make it sit in the tube but not so much that it is at spec (6-7NM maybe?). This will fix the stem in place as the expansion should cause the stem to not move. Make sure it is seated where you want it, then torque the stem to spec (or slightly below spec). Lastly, torque the expander plug to spec. This SHOULD stop all issues from occuring.

As one poster mentioned, the spacers are likely what was causing the periodic loostening. I think this is a viable explination, as the contraction of the plastic may explain why there was some slack after you altered the front end.

Also use carbon paste. It may stop some of the slack.

achin
Posts: 37
Joined: Sat Jul 04, 2020 4:41 pm

by achin

kieler2020 wrote:
Thu Jun 24, 2021 12:19 pm
So, to add my 2 cents worth to the discussion about loosening headsets, it seems like I've maybe found whats causing my problem. A few months ago I readjusted for a better fit and cut the steerer tube and since then it has always started loosening up. I've tried everything (carbon paste etc.) and it alwas came back after a few hundred kms. It never made sense because the expander, although crap and poorly fitting, wasn't pulling up even under 12Nm tension. On a whim today I tried to fit a feeler gauge in between the flat face of the steerer and the stem whilst still installed (at 5Nm). And what do you know? I can slide a 0.1 mm gauge right down both sides :shock: See photo (in case you're wondering, I use the Look supplied spacer under the top cap).

It turns out that either the front part of the steerer is very slightly narrower than the rear, or the stem itself is a asymmetrical. Since the stem is clearly designed so that most of the clamping surface area is on the two flat sides, my stem is only making contact towards the back half of the steerer tube (the front doesn't count as the stem is hollowed out there). So of course it will never hold tight.

I'm sending this to Look for a hopefully helpful response...

S
To piggy back on this, you might want to lower your expander plug by a couple mm. You need the top of the plug to have some space to allow the top cap to tighten... basically, you NEED extra space between the plug female connection and the plug to allow a clamping force to occur. Right now, you might be just tightening against the plug itself and not the stem. Heres a small diagram of shitty paint hopefully helping. I have seen this occur in other peoples bike and I have fixed it for them (on different stems etc.). Luckily I am an engineer and also do a lot of bike work, but this is not intuitive and due to the complex tightening system on this bike, its an easy mistake to do.

Image
https://imgur.com/aZcX5n9

nino10
Posts: 76
Joined: Sun Aug 09, 2020 2:32 pm

by nino10

kieler2020 wrote:
Thu Jun 24, 2021 12:19 pm
So, to add my 2 cents worth to the discussion about loosening headsets, it seems like I've maybe found whats causing my problem. A few months ago I readjusted for a better fit and cut the steerer tube and since then it has always started loosening up. I've tried everything (carbon paste etc.) and it alwas came back after a few hundred kms. It never made sense because the expander, although crap and poorly fitting, wasn't pulling up even under 12Nm tension. On a whim today I tried to fit a feeler gauge in between the flat face of the steerer and the stem whilst still installed (at 5Nm). And what do you know? I can slide a 0.1 mm gauge right down both sides :shock: See photo (in case you're wondering, I use the Look supplied spacer under the top cap).

It turns out that either the front part of the steerer is very slightly narrower than the rear, or the stem itself is a asymmetrical. Since the stem is clearly designed so that most of the clamping surface area is on the two flat sides, my stem is only making contact towards the back half of the steerer tube (the front doesn't count as the stem is hollowed out there). So of course it will never hold tight.

I'm sending this to Look for a hopefully helpful response...

S
Your steerer tube is too long for the Look construction - must end about 5mm under the clamping area of the stem (had my frame at Look Nevers France because of some difficulties and this was part of the solution):
https://forum.tour-magazin.de/showthrea ... ost6210655
- maybe helpful with google translation...

achin
Posts: 37
Joined: Sat Jul 04, 2020 4:41 pm

by achin

nino10 wrote:
Thu Jun 24, 2021 6:35 pm
kieler2020 wrote:
Thu Jun 24, 2021 12:19 pm
So, to add my 2 cents worth to the discussion about loosening headsets, it seems like I've maybe found whats causing my problem. A few months ago I readjusted for a better fit and cut the steerer tube and since then it has always started loosening up. I've tried everything (carbon paste etc.) and it alwas came back after a few hundred kms. It never made sense because the expander, although crap and poorly fitting, wasn't pulling up even under 12Nm tension. On a whim today I tried to fit a feeler gauge in between the flat face of the steerer and the stem whilst still installed (at 5Nm). And what do you know? I can slide a 0.1 mm gauge right down both sides :shock: See photo (in case you're wondering, I use the Look supplied spacer under the top cap).

It turns out that either the front part of the steerer is very slightly narrower than the rear, or the stem itself is a asymmetrical. Since the stem is clearly designed so that most of the clamping surface area is on the two flat sides, my stem is only making contact towards the back half of the steerer tube (the front doesn't count as the stem is hollowed out there). So of course it will never hold tight.

I'm sending this to Look for a hopefully helpful response...

S
Your steerer tube is too long for the Look construction - must end about 5mm under the clamping area of the stem (had my frame at Look Nevers France because of some difficulties and this was part of the solution):
https://forum.tour-magazin.de/showthrea ... ost6210655
- maybe helpful with google translation...
Ah yes, agree with this. Thats 100% your issue. The top cap is NOT resting on the stem, it is resting on the steerer.

You either need a small spacer to allow the plug to rest on the spacer (above), a spacer below to bring the stem up 2-3mm (to allow the plug to rest on the stem), or to cut the steerer by a few mm to rest below the stem.

kieler2020
Posts: 15
Joined: Mon Jun 15, 2020 12:40 pm

by kieler2020

That's not the issue. I mentioned in my post that I have a spacer under the top cap.

achin
Posts: 37
Joined: Sat Jul 04, 2020 4:41 pm

by achin

Have you tried adding a small 2.5mm spacer under the stem (not top cap) and seeing if it resolved your problem? Are you tightening the bolts in a correct order? Only reason I am asking is you should induce a compression force from the top cap downwards first (righten the stem down with the plug+the top cap first), then tighten the stem bolts, then tighten the plug up to spec and finally tighten the stem bolts and top cap at the end.

I remember thinking why I did it this way and it was because if you do it in any other order you may have slack in the stem area. If you tighten the stem bolt first, you cant fit the plug+the top cap down correctly. If you tighten the plug too much first, you will not compress the stem enough when you tighten the top cap and the stem bolts. Alternatively, the look spacer under the top cap may be preventing the stem from compressing with the 2 stem bolts, resulting in slack between the stem and steerer interface.

1) Fit the plug in the steere and tighten but NOT up to spec, just enough so it stays and you can tighten the top cap down while the stem can still move into the steerer
2) Compress the stem down into the frame with the top cap. Not up to spec.
3) Secure the stem bolts but not up to spec yet
4) (if your torque wrench cannot reach the plug bolt) Pull out the top cap, torque the plug up to spec, place the top cap back on and make sure it is compressed. Not up to spec yet.
5) Bring the plug up to spec
6) Bring the stem bolts up to spec.

This should remove all slack from the stem. Make sure you do have the space for compression as per what I posted earlier. If you are doing all this, then maybe it is your stem/steerer being the issue, but it shouldnt be the case. I think this is just a really unnecessarily complicated front end design... as per typical "French" standards
Last edited by achin on Thu Jun 24, 2021 9:20 pm, edited 1 time in total.

nino10
Posts: 76
Joined: Sun Aug 09, 2020 2:32 pm

by nino10

kieler2020 wrote:
Thu Jun 24, 2021 8:27 pm
That's not the issue. I mentioned in my post that I have a spacer under the top cap.
Based on my experiences and Look France (Grofa)...:
Spacer under the Top Cap schouldn't work fine.
And it should be about 5-6 mm.
Expander lower - tightened a bit more than 8NM.
Stem a bit more than 5NM.
(Top cap not more than 12 NM)
If nothing helps - sometimes the ADS stem is not produced properly, so you could try another one (but the points above schould be followed).

Defender110
Posts: 26
Joined: Mon Mar 09, 2020 11:21 pm

by Defender110

kieler2020 wrote:
Thu Jun 24, 2021 8:27 pm
That's not the issue. I mentioned in my post that I have a spacer under the top cap.
Have you tried the incremental tightening we've posted about here - we've had success in eliminating the looseness via this method. Meaning, don't take it all apart again when it comes loose - just loosen the stem bolts slightly and re-tighten the top cap some more (assuming its not beyond 12nm spec) then tighten stem bolts. I actually rode for a week with the stem side covers off and did this on rides - after incremental tightening once or so I didnt get any more looseness for the rest of the season (6+ months). Not saying your issue isnt different - just repeating whats worked for some of us. In my case, I'm pretty sure its the plastic headset spacers seating and compressng slightly under load and vibrations of riding. That slackness eventually gets removed through incremental tightening and then it goes away.

by Weenie


Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

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