# Rigid 29" on a Klein Mantra



## the0r1st (Jul 21, 2010)

Anyone put a rigid 29" on a Klein Mantra?


----------



## doc Zox (Sep 16, 2010)

that might be kinda cool, i wonder if there would be toe strike

i can mock it up in photoshop

ding with a squish 29 front


----------



## NEPMTBA (Apr 7, 2007)

Looks pretty cool...
...nice Klein also!


----------



## H_Tuttle (Feb 27, 2007)

Dats a high rock garden bb on that one now


----------



## the0r1st (Jul 21, 2010)

nice.

Did similar









But went back with a 100mm


----------



## girlonbike (Apr 24, 2008)

Wow. Have you taken that on actual mountain biking trails? That doesn't look like it'll ride well. How was it?


----------



## the0r1st (Jul 21, 2010)

69er Mantra IMO is better downhill, but it takes more to keep it pointed straight. Probably has to do with the geometry. That's why I'm considering putting a rigid fork on and trying to keep similar geometry, already have the wheel. It's probably going to be pretty goofy, but just play in.


----------



## 1 cog frog (Dec 21, 2004)

If I remember correctly, I have seen an early Mantra set up rigid front. It always perplexed me. Why would you want 5" of rear travel and no front?

Even with a shorter 29er fork and a big tire, seems like the ride would be pretty unbalanced.

But hey, if you have the stuff, go for it! :thumbsup:

Curious to hear how it works, so post pics and a ride review!

frog


----------



## shibiwan (Sep 2, 2012)

1 cog frog said:


> If I remember correctly, I have seen an early Mantra set up rigid front. It always perplexed me. Why would you want 5" of rear travel and no front?
> 
> Even with a shorter 29er fork and a big tire, seems like the ride would be pretty unbalanced.
> 
> ...


The original design was for a rigid front and supposedly hits to the front would be absorbed by the rear suspension.

-S


----------



## StrangeBike13 (Jan 28, 2011)

Shiiwan hits it on the head. Darrell Voss explained why the prototype Mantras that he brought up for a magazine test were hard noses, and his theory was that the compliance in the middle helped you up front. I disagreed, but he was much taller than I, so I didn't disagree to his face. It isn't true, but its a great Voss-ism! All these neat pics are making me miss my Mantras! I wish I had bought one of the prototypes. They had those huge Klein stems and forks, and were very light, and very cool indeed. And climbed ultra-steeps like nothing else I've ever ridden!


----------



## shibiwan (Sep 2, 2012)

StrangeBike13 said:


> I disagreed, but he was much taller than I, so I didn't disagree to his face. It isn't true, but its a great Voss-ism! All these neat pics are making me miss my Mantras! I wish I had bought one of the prototypes. They had those huge Klein stems and forks, and were very light, and very cool indeed. And climbed ultra-steeps like nothing else I've ever ridden!


I agree with you! LOL

I bought mine used from a LBS that does used bikes after I had done some research. Tried out several bikes there and some new bikes at other shops and still found that I preferred the fit of the Mantra and how it rides/handles.

It's one nimble bike and despite its age, it climbs really well.

I've started updating the bike, changing out worn out stuff, put in new carbon bits, etc.... and for my next project I'm going to design/make my own rear disc brake adaptor (I own an engineering company with our own CNC shop). I don't quite like all the existing/available choices of 22mm brake adaptors (A2Z, B&S) because they are made out of stamped steel and will flex.

Here's a pic of my updated Mantra:









-S


----------



## doc Zox (Sep 16, 2010)

discs make a difference in the brake bob


----------



## StrangeBike13 (Jan 28, 2011)

My favorite Mantra story: One day, I got a Mantra for a Bicycling or Mountain Bike test. I had ridden it once at a not-so-steep trail area, and was lukewarm on the bike. It was a faded orange one like one of the bikes pictured above. My friend John McClain wanted to try it on a day when I couldn't ride, so he picked it up and took it to the feared "Hard Side" of Whistle Lake, in Anacortes, WA (some the steepest climbs around, one after another). He got back, and said, "Did you ride that bike? Did you see how it climbs! Holy crap!" He was so enthused (and that takes a lot with John) that we went to Whistle the next night, and traded off between a Trek Y bike and the Mantra. Holy crap! The Mantra just would not spin- if you didn't run out of leg strength or balance, you climbed the hill. The Y bike was the opposite- it would not grip standing up. We both climbed the steeped hill (the Mad MuFu) several times on the Mantra, and never made it even half way on the Y bike. Fell in love with the Mantra that night; McClain still has one.


----------



## shibiwan (Sep 2, 2012)

doc Zox said:


> discs make a difference in the brake bob


Saw your post in another thread, doc, but those calipers are nice but next to impossible to find these days. :thumbsup:

....and besides, I keep looking at the set of Juicy Ultimates on my table. Can't wait to put them on. LOL.

-S


----------



## girlonbike (Apr 24, 2008)

shibiwan said:


> ....and besides, I keep looking at the set of Juicy Ultimates on my table. Can't wait to put them on. LOL.
> 
> -S


I have a set on a bike. Can't say I'm a big fan.


----------



## the0r1st (Jul 21, 2010)

They do climb like a monkey.


----------



## shibiwan (Sep 2, 2012)

girlonbike said:


> I have a set on a bike. Can't say I'm a big fan.


Hrm.... got them used... maybe that's why they were cheap.


----------



## jeff (Jan 13, 2004)

I once built a SS Mullet out of a Catamount SL. Not as active a design as the Mantra but a well done URT all the same. I used a friends custom 26" disc fork that was able to swallow an Exiwolf. It was a very fun bike and with the short AC measurement, the handling was not compromised. Do to the lackluster steering precision of the Judy that was on there prior I'd say it was much improved. The brake induced inchworm effect was minimized also. No pics of the build exist. A low ac fork is what you need.


----------



## the0r1st (Jul 21, 2010)

jeff said:


> I once built a SS Mullet out of a Catamount SL. Not as active a design as the Mantra but a well done URT all the same. I used a friends custom 26" disc fork that was able to swallow an Exiwolf. It was a very fun bike and with the short AC measurement, the handling was not compromised. Do to the lackluster steering precision of the Judy that was on there prior I'd say it was much improved. The brake induced inchworm effect was minimized also. No pics of the build exist. A low ac fork is what you need.


I agree, do you have a recommendation I need a fork with an ac of 16.375" to keep the same geom.


----------



## 1 cog frog (Dec 21, 2004)

You will not fit a 29er tire in a fork with a 390mm a-c.

The shortest production fork I know that will hold a 29er tire is a surly 1x1 fork with an a-c of about 410mm. It is designed for a 26" wheel so you will have to run a disc brake as the canti studs won't line up with the rim. I was able to fit a 2.3 Exiwolf on a Sun CR-17 rim using a disc brake, and the minimal knobs of the Exiwolf _barely_ cleared the underside of the fork crown. A smaller tire would give you a bit more wiggle room, but compromise on the "suspension" up front.

frog


----------



## chefmiguel (Dec 22, 2007)

Perhaps a 650b wheel would be a better option.


----------



## girlonbike (Apr 24, 2008)

Or a 26" wheel. Or get a 29'er.


----------



## 1 cog frog (Dec 21, 2004)

girlonbike said:


> Or a 26" wheel. Or get a 29'er.


Now, now, don't go getting all logical on us! 

frog


----------



## cgarai (Sep 7, 2010)

Theorist, did you ever get beyond the theory? Did you try the 29 on the Mantra? 

It's a cool thread and I'm thinking of doing the same to mine.

Chris


----------



## the0r1st (Jul 21, 2010)

Still looking for a fork, winter anyways and not in a hurry. What you got? Post a picture.


----------



## dogspeed (Aug 6, 2010)

*FrankenKlein Mantra Hard Nose*








This project came to fruition as a result of folklore, curiosity and experience riding Mantra(s) for almost 20 years, and, I've got to say, I'm impressed!
This is a capable, lightweight, predictable, XC, flowing single track, beast of a bike. Climbs as good as FS if not better. Requires revision of riding style - especially rocky/rooty fast downhills as I need to loosen my grip, or get rattled.
It doesn't fully eliminate the stink-bug/inchworm under braking but tames it to the point of rider, rather than bike, error.
Currently 29x2.1/26x2.1. I believe a larger volume tyre (2.25/2.3) up front would help with suspension and taction duties.


----------



## RyanMorph (Jun 14, 2017)

dogspeed said:


> View attachment 1129835
> 
> This project came to fruition as a result of folklore, curiosity and experience riding Mantra(s) for almost 20 years, and, I've got to say, I'm impressed!
> This is a capable, lightweight, predictable, XC, flowing single track, beast of a bike. Climbs as good as FS if not better. Requires revision of riding style - especially rocky/rooty fast downhills as I need to loosen my grip, or get rattled.
> ...


This is very interesting but seems dangerous to ride this with a rigid fork to me. Isn't the point of the Mantra to have very light shock movement on the front? I feel like a rigid would make stinkbuggin worse.


----------



## colker1 (Jan 6, 2004)

dogspeed said:


> View attachment 1129835
> 
> This project came to fruition as a result of folklore, curiosity and experience riding Mantra(s) for almost 20 years, and, I've got to say, I'm impressed!
> This is a capable, lightweight, predictable, XC, flowing single track, beast of a bike. Climbs as good as FS if not better. Requires revision of riding style - especially rocky/rooty fast downhills as I need to loosen my grip, or get rattled.
> ...


Coool! And it looks balanced. It should rock as a technical garden bike. I would try to get rid of the rim brake.


----------



## dogspeed (Aug 6, 2010)

*FrankenKlein Mantra 69er Hard Nose Evo 18*








Latest evolution of FrankenKlein.
Shorter fork. Axle to crown reduced from 470 to 420mm => more direct and planted steering, less flippy floppy on steep switchback climbs.
Fatter (decent) rubber, now 2.3 f&r => More forgiving, more grip.
36t oval N/W chainwheel (reduced from 44t) => this bike is more capable than I imagined.
Yep, still got the 29" on there, it's just the framing of the photo making it look balanced.
If only this model year had a rear disk brake boss...


----------

