# Wren Stem 50mm 75gm



## Legbacon (Jan 20, 2004)

When I saw this I thought of the WWs.

Review: Wren Sports? ultralight aluminum stem is scary light - Bikerumor


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## scant (Jan 5, 2004)

I'm using a wren stem on my XC bikes & its fine.


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## jestep (Jul 23, 2004)

I'm using an 80mm one. The gloss finish on them is amazing, I'm not typically a fan of gloss anno, but these are very nice. The lack of material for the threads on the steerer side is a bit scary, literally there's hardly anything there at all. They also use small M4 bolts, could probably save a few more grams with ti bolts since the ones that came with mine were just anodized aluminum.


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## sryanak (Aug 9, 2008)

jestep said:


> I'm using an 80mm one. The gloss finish on them is amazing, I'm not typically a fan of gloss anno, but these are very nice. The lack of material for the threads on the steerer side is a bit scary, literally there's hardly anything there at all. They also use small M4 bolts, could probably save a few more grams with ti bolts since the ones that came with mine were just anodized aluminum.


Aluminum bolts should be lighter than ti bolts. You relly can't make a bolt smaller than it needs to be so lighter weaker aluminum wins over heavier stronger titanium. There are some places where stronger is better though.


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## scant (Jan 5, 2004)

I'm pretty certain, borderline postive that the bolts are steel


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## jestep (Jul 23, 2004)

scant said:


> I'm pretty certain, borderline postive that the bolts are steel


Mine are definitely black so I was assuming they were anodized aluminum. I'll check with a magnet when I get to the house today.


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## lRaphl (May 26, 2007)

A magnet wont work on stainless steel...


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## jestep (Jul 23, 2004)

lRaphl said:


> A magnet wont work on stainless steel...


I just checked and they are magnetic. It looks like they are painted, so painted carbon steel, I'm guessing?


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## Crossmaxx (Dec 2, 2008)

It's stupid and borderline suicidal to run aluminum bolts on the stem.


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## RussJ (Nov 18, 2015)

Hi, Russ from Wren. I just saw the comments about the bolts used in the Wren stems. The Wren bolts are ChroMoly steel. We use ChroMoly for strength and a little weight savings. Biggest weight factor is the Torx bolt design. Torx bolts are smaller, lighter and stronger than comparable allen bolts. Our bolts are also lighter than Ti allen bolts. Remember to always use a Torx wrench on the bolts. Thanks for the interest in our stem!


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## Jayem (Jul 16, 2005)

One negative I found is that most multi-tools do not have T20 drivers on em, so if your stem loosens up, sometimes due to a real hard hit or whatever, you are out of luck or you need a different tool or an additional tool, which most likely earns you back the weight you saved. My Ritchey stem is also T20. Light, but probably not worth it for this reason.


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## RussJ (Nov 18, 2015)

Excellent observation, Jayem, and one we realized quickly, so all of our stems are now T25. We have maybe 50 of the original spec of T20 out there. We have replaced some already. If anyone has an early Wren stem with T20, send us a copy of your receipt and we will send you a set of T25 bolts.
Russ / Wren


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## MountainBored (Aug 4, 2016)

This stem is going on my Xmas wish list!
😎


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## eri (Sep 4, 2012)

RussJ said:


> Excellent observation, Jayem, and one we realized quickly, so all of our stems are now T25. We have maybe 50 of the original spec of T20 out there. We have replaced some already. If anyone has an early Wren stem with T20, send us a copy of your receipt and we will send you a set of T25 bolts.
> Russ / Wren


Jeese man. What the heck is going on here?

By responding with facts on this forum you are making other manufacturers look bad.

You just talked me into ordering one, a 90mm unit, for my ss.


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## jochribs (Nov 12, 2009)

Jayem said:


> One negative I found is that most multi-tools do not have T20 drivers on em, so if your stem loosens up, sometimes due to a real hard hit or whatever, you are out of luck or you need a different tool or an additional tool, which most likely earns you back the weight you saved. My Ritchey stem is also T20. Light, but probably not worth it for this reason.


Hmmm...that's weird. Both of my multi tools have both T20 and T25 on them. I have a Ritchey 260 too. Never been a problem with the T20's. You think they're bad...the earlier 260's had 3mm allen heads.

Russ, do you guys have torque specs on your stems? And will that vary between the T20 and 25? I'll be grabbing one of your stems for my son's build for sure. They look awesome.


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## Jayem (Jul 16, 2005)

jochribs said:


> Hmmm...that's weird. Both of my multi tools have both T20 and T25 on them. I have a Ritchey 260 too. Never been a problem with the T20's. You think they're bad...the earlier 260's had 3mm allen heads.


That's a rarity, I had multiple multi tools and no T20s, I looked for a while before I found one, but it's not what I'd call common, you are just lucky. In any event, it's cool that Wren is giving T25s to people (a common size).


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## santabooze (Oct 14, 2010)

I just ordered 2 of these stems to replace my Turbine stems. 60mm of course


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## RS VR6 (Mar 29, 2007)

I have a 40mm in excellent condition if anybody is interested.


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## RussJ (Nov 18, 2015)

jochribs said:


> Hmmm...that's weird. Both of my multi tools have both T20 and T25 on them. I have a Ritchey 260 too. Never been a problem with the T20's. You think they're bad...the earlier 260's had 3mm allen heads.
> 
> Russ, do you guys have torque specs on your stems? And will that vary between the T20 and 25? I'll be grabbing one of your stems for my son's build for sure. They look awesome.


Yes, the torque spec is 6Nm. Either T20 or T25. Thanks! Russ


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## jochribs (Nov 12, 2009)

Ah, that's nice that they can handle a bit more torque. Most stems are calling for 5 at the max. You guys recommend going for a little lower, say 4.5 to 5, and seeing if that's sufficient?


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## RussJ (Nov 18, 2015)

jochribs said:


> Ah, that's nice that they can handle a bit more torque. Most stems are calling for 5 at the max. You guys recommend going for a little lower, say 4.5 to 5, and seeing if that's sufficient?


Just need to make sure your bars are tight without exceeding 6Nm. Thanks!
Russ / Wren


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## eri (Sep 4, 2012)

Stem arrived Saturday. 90mm really is only 84 grams. Really smooth finish inside and out, whole thing is cold like metal but light like plastic and sculpted like liquid.

I'm sorry to see the mighty chromag go, loved its graphics and interesting machined finish.

The -6 degree drop gets the bars as low as brake lever clearance allows.

What is surprising is how much I notice the 125 gram weight reduction. Used to be the back of the bike felt light, the front heavy, now it feels really balanced.

My impressions: weight reduction feels like a big deal. Climbing I noticed the stem is not nearly as stiff as the chromag, but not noodley enough to matter. Mainly small sharp shocks are damped.


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## kylepeveto (Apr 25, 2006)

I just bought one of these Wren stems. I’m kind of afraid of using it. How are they holding up over the long term?


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## scant (Jan 5, 2004)

2years old, no issues for me


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## GRPABT1 (Oct 22, 2015)

I ordered a 40mm and it's on the way. They assured me it's certified for DH use so that's good enough for me on my enduro bike.


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## MountainBored (Aug 4, 2016)

My 50mm stem is flawless after 1.5 years. I send it down lots of rocky trails and have crashed several times. No worries about the stem.


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## eri (Sep 4, 2012)

Update after almost 2 years: stem will no longer hold, headset loose after each ride. Cleaned fork steerer with acetone, etc, but stem just won't hold the headset at max recommended bolt torque. Stem doesn't move side to side but slides upwards during rough descents. Top and bottom edges and parts of the inside of the wren show worn paint. I put the chromag back on and it is solid as a rock. I might try harder to get it to hold - ideas?

I'm 180 (but carry 10-15 lbs on rides), ride lots of steeps with roots and 1-2' steps, hardtail with 120mm fork.


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## phlegm (Jul 13, 2006)

eri said:


> Update after almost 2 years: stem will no longer hold, headset loose after each ride. Cleaned fork steerer with acetone, etc, but stem just won't hold the headset at max recommended bolt torque. Stem doesn't move side to side but slides upwards during rough descents. Top and bottom edges and parts of the inside of the wren show worn paint. I put the chromag back on and it is solid as a rock. I might try harder to get it to hold - ideas?
> 
> I'm 180 (but carry 10-15 lbs on rides), ride lots of steeps with roots and 1-2' steps, hardtail with 120mm fork.


Carbon paste? Might be just enough to allow it to hold at recommended torque.


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## thesmokingman (Jan 17, 2009)

eri said:


> Update after almost 2 years: stem will no longer hold, headset loose after each ride. Cleaned fork steerer with acetone, etc, but stem just won't hold the headset at max recommended bolt torque. Stem doesn't move side to side but slides upwards during rough descents. Top and bottom edges and parts of the inside of the wren show worn paint. I put the chromag back on and it is solid as a rock. I might try harder to get it to hold - ideas?
> 
> I'm 180 (but carry 10-15 lbs on rides), ride lots of steeps with roots and 1-2' steps, hardtail with 120mm fork.


Are the bolts stretched out? It reads like they are no longer holding. The wren is built very weight weenie so I'd lean towards more xc than chunk with it.


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## Taildragger (Mar 13, 2005)

Sounds like a 'star nut' issue, did you check that?


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## phlegm (Jul 13, 2006)

Taildragger said:


> Sounds like a 'star nut' issue, did you check that?


That's a good point. I'm curious if the replacement chromag eventually loosens too? If so, it is that nut/expander. If not, something else.


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## thesmokingman (Jan 17, 2009)

The star nut is for back up, its not intended to hold it together indefinitely. The stem still has to perform its function whether there's a star nut or not.


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## phlegm (Jul 13, 2006)

thesmokingman said:


> The star nut is for back up, its not intended to hold it together indefinitely. The stem still has to perform its function whether there's a star nut or not.


That's correct, but if the stem "grip" is marginal, the starnut/expander could also be failing. Either way you have a potentially dangerous issue.


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## thesmokingman (Jan 17, 2009)

phlegm said:


> That's correct, but if the stem "grip" is marginal, the starnut/expander could also be failing. Either way you have a potentially dangerous issue.


Poster has swapped the failing stem so no issue. I'm just curious whether the bolts are stretched or the stem is fatigued. These wren stems are very weight weenie man, the stem bolts are stupid lightweight (M3) so I wouldn't be surprised if they gave up.


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## eri (Sep 4, 2012)

Well... chromag has lasted now for more than 7 hours of pounding and headset is still nice and tight.

Starnut: like others have said it shouldn't be involved in holding stem in place, its for setting the bearing load.
M3 Bolts: they are small, but they are steel and they laugh at that thin aluminum. I very much doubt the steel bolts are aging or stretched.

The wren stem... to my eyes it looks 'fine' in the glare of the kitchen lights. The part that grips the steer tube is greatly hollowed out, the chromag has a full radius to grip the steer tube.

When I tighten the wren onto the steer tube it sort of seemed to deform, to my eyes, in the dark garage.

On both stems I have about 2mm of gap between top of stem and top of steer tube. Maybe this is the sort of stem that needs a spacer on top of the steer tube, so has a full steer tube to grip?

Well... the wren is super light but I'm surprised how much more I like having a tight headset and solid feel at the bars. Just a small amount of play at the headset was making me consider upgrading to a float 34, but with a tight headset I'm now really happy with the 32.

I'm sort of wondering if sanding steer tube or stem with a course grit sandpaper might improve the grip and get the stem working again, but now that I've rediscovered a stiff stem I have stopped really caring.

Prolly for the best.


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## phlegm (Jul 13, 2006)

eri said:


> ...
> 
> I'm sort of wondering if sanding steer tube or stem with a course grit sandpaper might improve the grip and get the stem working again, but now that I've rediscovered a stiff stem I have stopped really caring.
> 
> ...


I mentioned carbon paste above, which would achieve the same thing, however I've never had to use it on the steerer/stem interface.


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## RX93 (Apr 30, 2018)

I ordered a stem from them and they're back to using T20 screws.


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## thesmokingman (Jan 17, 2009)

RX93 said:


> I ordered a stem from them and they're back to using T20 screws.


I was referring to the thread pitch, but yea still teeny sized bolts T20 included. From the bikeradar review, which apparently means they still have not improved the strength of the bolts.

"To get right to the point, in my opinion T20 bolts just don't cut it. Fortunately, Wren seems to agree. Before I had even voiced my concerns, they had already made a running change to T25 Torx bolts. Problem solved. That should make it a lot easier to install and adjust, not to mention ensure that you have the right tool on your multi-tool."


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## GRPABT1 (Oct 22, 2015)

eri said:


> On both stems I have about 2mm of gap between top of stem and top of steer tube. Maybe this is the sort of stem that needs a spacer on top of the steer tube, so has a full steer tube to grip?


This. I wouldn't try and run such a weight weenie part without giving it the best chance it can to work, pretty sure no stem manufacturers would recommend running the stem proud of the top of the steerer tube. I always cut my steerers with plenty of extra height, if anything it helps for resale or potential frame upgrades.

Carbon paste on the steerer and a little grease on the threads and under the bolt heads is also a good idea.


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## phlegm (Jul 13, 2006)

GRPABT1 said:


> ...
> 
> Carbon paste on the steerer and a little grease on the threads and under the bolt heads is also a good idea.


FYI, the opposite combo of grease on the steerer and grit on the bolts is bad.


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## GRPABT1 (Oct 22, 2015)

phlegm said:


> FYI, the opposite combo of grease on the steerer and grit on the bolts is bad.


Yes that would be ungood.


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## Jayem (Jul 16, 2005)

I always use friction grease on stems and handlebars, no matter the material.


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## Turd (Jul 21, 2005)

I’d double check the 2mm , I don’t know what wren specs. (Ritchey specs 2mm) Possibly the top cap is bottoming out on the steerer inhibiting bearing load. Most top caps have a “step” that goes inside of the stem. I’ve had that problem, felt fine in the shop but no go on the trails. 
Just slap a thin spacer on top of the stem to test. Is the star nut deep enough? I’ve also failed on that account and the threads bottom out before full bearing load.


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## Just J (Feb 14, 2005)

Mikeetheviking just showed me the Wren stems today, I had no idea about them but I'm intrigued and considering one for a new build! 

I can't help wondering though, do you think they're a good idea for a 235lbs rider?


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## GRPABT1 (Oct 22, 2015)

Just J said:


> Mikeetheviking just showed me the Wren stems today, I had no idea about them but I'm intrigued and considering one for a new build!
> 
> I can't help wondering though, do you think they're a good idea for a 235lbs rider?


Until recently I was heavier than that and I've raced local enduros on my 40mm Wren stem. It's certified for DH after all.


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## Just J (Feb 14, 2005)

GRPABT1 said:


> Until recently I was heavier than that and I've raced local enduros on my 40mm Wren stem. It's certified for DH after all.


Exactly what I was wanting to hear, thank you!


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## padrefan1982 (Mar 2, 2005)

RX93 said:


> I ordered a stem from them and they're back to using T20 screws.


Old thread I know, but figured this email I got from Wren today could be helpful. Wren is back to T20 bolts full time, with no option (via them) for T25s:

"_Our initial run of stems came with T25 bolts for convenience because many multi-tools have T25 wrenches. However, after further ISO testing we determined that the T20 bolts were stronger. As safety is always our first concern when designing our products, we immediately switched to T20. The replacements we offered, as mentioned in some articles, were T20 for T25 bolts. T25 bolts are no longer available.

Bolt specs:
Material: Chromoly steel
Size: M4
Length: 15 mm
Thread pitch: 0.7 mm
Head: Torx T20_"


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## mrbadwrench (Sep 13, 2016)

Weren't there reports of bolt heads popping off these?


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## Chicane32 (Jul 12, 2015)

mrbadwrench said:


> Weren't there reports of bolt heads popping off these?


Not one that I've read.


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## xc71 (Dec 24, 2008)

mrbadwrench said:


> Weren't there reports of bolt heads popping off these?


Several. Post # 23, 29, 31 etc.
https://forums.mtbr.com/weight-weenies/pivot-mach-4-xc-build-1075642.html


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## mrbadwrench (Sep 13, 2016)

xc71 said:


> Several. Post # 23, 29, 31 etc.
> https://forums.mtbr.com/weight-weenies/pivot-mach-4-xc-build-1075642.html


Thank you. I remember reading that thread but couldn't find it again. That's why I stick with kalloy uno. Half the price, only 20g more , and super reliable.


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## Wheelspeed (Jan 12, 2006)

Sorry to pull up an old thread, but I found this because I'm stem shopping. I read the original review link in the very first post and saw that they updated that review to say that the Wren stem had failed with the original smaller bolts.

I see ENVE makes a 100g stem for 35mm bars, but very pricey. (But fine with converting to 31.8mm since personally I think the 35mm thing is idiotic.)

I like my Uno 7 on my roadbike, but I see they don't make a short enough stem for the current long/low/slack mtbs. I'm interested in going a little shorter than my current 50mm... down to 40mm or 35mm I guess. (Because apparently I'm not loving the steeper STA trend so my saddle is almost all the way back.)

Any thoughts on 100g-stems for around $100 or so? It's a full-suspension xc/trail bike, so the stem won't take too bad of a beating. (Not as bad of harsh impacts as roadbike stems go through with no suspension and 80psi tires.)

EDIT- Not meaning to lock in at $100... I just mean cheaper than the $230 or so that ENVE costs for the CF stem. Honestly I'd be a bit embarrassed to show up with an ENVE stem in front of my friends it's so pricey... like showing up at a ride with gold chains around my neck.


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## rapsac (Sep 26, 2004)

https://www.newmen-components.de/en/46/mtb/stems/evolution-sl-3184/


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## jestep (Jul 23, 2004)

Wheelspeed said:


> Sorry to pull up an old thread, but I found this because I'm stem shopping. I read the original review link in the very first post and saw that they updated that review to say that the Wren stem had failed with the original smaller bolts.
> 
> I see ENVE makes a 100g stem for 35mm bars, but very pricey. (But fine with converting to 31.8mm since personally I think the 35mm thing is idiotic.)
> 
> ...


The raceface turbine 31.8 and turbine R 35 are a bit above 100g and you should be able to find them for under $100. I can't imagine them not handling anything you could possibly throw at them.


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## B R H (Jan 13, 2004)

My Wren stem has seen a lot of use and a fair amount of abuse with no trouble at all even after a recent crash that snapped my handlebars clean near the brake lever in a head-on crash. I weigh about 175 with gear. Mine has the small bolts. I always use a torque wrench and friction paste. These obviously aren’t as stiff as heavier stems but they seem to be plenty tough.


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