Results 1 to 9 of 9
  1. #1
    boba
    Reputation:
    Join Date
    Dec 2007
    Posts
    133

    Replacement for Gemini

    Hi...I am an older rider on Vancouver Island.Canada. Our riding is mild North Shore riding, wet, rocky & rooty with steep descents...We ride all year round. Our riding makes Moab...where I have been three times...seem flat. Being older, I no longer do jumps.

    My 03 Gemini has a 67degree head angle and 71 seat angle and weighs 34.4 lbs. Goes down great but is tiring to climb with for an hour and a quarter before the fun starts. I was the first in our group of much younger guys to go with a light bike...ie from a 41 lb. Turner RFX to the Gemini, but others are now getting Slayers, Specialized Enduros, Nomads etc. So, the question is....The Ibis Mojo is beautiful, light and georgeous, but with a 69/73 degree set of angles, it is steeper than I am used to.....but if I put on a 160mm. fork, it is more relaxed. Some of you must ride pretty rough terrain, bike parks etc? How do you find the bike in steep, rough terrain. Does the lower bottom bracket seem a problem? 13.22 inches vs the 14.29 in the Gemini. Any comments would be appreciated. My wife rides very well, so if I get one, I have to buy two....so we are talking a few dollars...thanks, bob.

  2. #2
    Mojo0115
    Reputation:
    Join Date
    Nov 2004
    Posts
    1,667
    I ride my mojo in colorado and utah a lot and it is part way through it's 2nd winter at moab. My only comparison when it comes to steep, technical riding is my downhill bike (and my old bike but that is not a worthwhile comparison).

    I have a very short stem on my mojo and run it with a maveric speedball seat post. Between those two it feels very stable on the steep stuff. But I haven't ridden it on the north shore yet and am looking forward to taking it there next summer. I recently just put a 160mm fork on it (lyrik 2 step) but haven't really been able to give it a good work out yet with just 2 days at moab on it so far.

    As far as the bottom bracket, my old bike was a Fisher Cake that had a high BB as well and to be honest I had more pedal strikes on my old bike than I do with my mojo. But the mojo keeps momentum much better through rough terrain and it is much easier to time your pedal strokes in rock gardens. For steep off-camber sections I again ratchet pedal if needed. Rolling of things when I should be jumping them has occasionally caught my bashguard - but that is why I have it instead of a big ring.

    But, I haven't really pushed myself or my mojo to much into the realm of very rough and very steep at the same time. Either of them and I know for certain the mojo is a great fit - both together and I am not the guy to comment.

    Try and arrange a demo and take it out and see how it feels. Even a standard store build should be able to give you a sense of what it is capable of.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Dec 2007
    Posts
    66
    Bob,

    You seem to be at a similar point in your riding to myself see my parallel thread;

    I know that everyone hates Mongoose, but...

    My Nomad is just a bit too heavy and capable for my riding, now I seem to have three options;

    1. Make the Nomad lighter
    2. Buy another Heckler
    3. Buy the Mojo SL and fingers crossed, Ibis will replace any bits of the frame that may fail

    I heart just loves the look of the SL but I'm getting confused messages from my brain!

    I could replace my HT with the SL but then I won't use the Nomad much and will wish I still had a HT

    It's a big decision this one - perhaps I'll just take up road riding

  4. #4
    boba
    Reputation:
    Join Date
    Dec 2007
    Posts
    133

    Gemini/Nomad

    Thanks for your reply...Whatever I do, I will keep the Gemini for a while...For me, a big mistake would be to sell it before I am completely satisfied that the Mojo will do most evrything I want it to. The biggest issue for me with the Mojo is head tube angle, but with a 160mm lyric two step or similiar fox, the angles will be more relaxed. As well, the bottom bracket is 3/4 of an inch higher and with a bashguard (mandatory where we ride), it should be OK.

    I am a fairly strong rider (but over 60) and ride with a group of 40 to 54 year olds. We ride all winter (at night) and Sundays...We all bought big (40lb+) bikes years ago and four years ago, I was the first to go with a 34lb. freeride style bike...the Gemini. Now, others are getting Nomads etc. and climbing faster. I am looking at what will carry me for the next four or five years. 27 lbs of Mojo really appeals. Since I posted, I found that the Heckler has similiar angles and BB height to the Mojo and we have two excellent rider who love their Hecklers. My wife who is ten years younger has a Gemini as well, and if I get a Mojo, she will too. The Mojo Carbon sounds like the way to go... I think the SL with carbon cups is more than I need and a lot more money as well. Did you buy a frame and build it up or ???? What hub/wheels do you use. bob

  5. #5
    boba
    Reputation:
    Join Date
    Dec 2007
    Posts
    133

    Gemini/Mojo

    Sean...thanks for the post. Please let me know who the bike handles with the new Lyric 2 step fork. I would want to go that way for riding on Vancouver Island...

    bob

  6. #6
    www.derbyrims.com
    Reputation: derby's Avatar
    Join Date
    Jan 2004
    Posts
    6,788
    The geometry of a slacker steering angle produces three things.
    1, it increases steering trail which slows steering for reduced twitchiness or off-direction feedback at higher speeds, while increasing floppy and misdirected steering at lower speeds.
    2, increases pitch forward (dive) from braking deceleration weight shift.
    3, it lengthens the wheelbase forward of the rider weight.

    To me it sounds like your riding is not really high in speed, but more technically difficult, where low speed steering balance and less brake dive is desirable. A steeper head angle benefits these two requirements.

    But a steeper head angle shortens the wheelbase ahead of the rider weight which is not desirable for steeper downhill or difficult drop offs.

    Every degree of head angle difference produces a wheelbase difference of about 1/2 inch.

    So if you go to a steeper head angle from your comfortable Gemini’s 67 degrees to a Mojo or Heckler’s 69 degrees than you loose about 1 inch of wheelbase ahead of the rider weight.

    If you use a 160mm travel fork the Mojo frame geometry would be slackened to 68/72 degree head/seat angles. (And a 13.5 inch BB using the OEM Kenda Nevegal 2.1 size tires – a 2.4 tire will get you about 13.75 inch BB height before sag.)

    So to have the same comfort and confidence on the Mojo (or Heckler) with a 160mm fork going downhill and off difficult drops, then fitting to about a 1/2 inch longer top tube and 1/2 inch shorter stem than your Gemini fits you now should give you nearly the same rider weight distribution behind the front wheel. Plus you will have quicker steering for easier climbing balance and less brake dive than the Gemini with the same fork.

    You would need to adjust the seat further back on the rails about 1/2 inch for the same overall fit over the cranks as you had with the Gemini’s seat center. But you may want to keep the seat more centered on the Mojo for an easier climbing position over the pedals and just bend your elbows a little more climbing when it’s steep.

    PS: If you see JimC on your trails, please say Hi! to him for me. I hope to get up your way to venture into your rain forests someday (two weeks vacation time I get isn't enough to get away very far).

  7. #7
    mtbr member
    Reputation: Alabama's Avatar
    Join Date
    Aug 2007
    Posts
    72
    I have a Gemini and the WTF SL. I love the Gemini down the hill and hate it when its time to climb. I truly felt as if I was going to rip the manitou off the SL on some of descents that the Gemini handled with ease. However, the build on my two bikes are so different. I have Fox coil suspenders front and rear with big fat Kendas on the cracknfail. The WTF build is all about XC. If I was not keeping the Gem, I would have built the SL differently. My ultimate goal is to equal my descent speed with the SL. Unfortunately, it means that my 21.9 pound bike now weighs 23.4 with the more aggressive gravity equipment and I foresee another 2lbs being added in the future. Keep your Gem and add a SL. Truthfully, you will never ride the Gem again, but it will keep you from building a heavy SL.

  8. #8
    boba
    Reputation:
    Join Date
    Dec 2007
    Posts
    133

    reply to Derby...Gemini / Ibis

    Thanks Derby....You seem up on angles, geometry etc.

    My 03 Gemini has a 24.6" horizontal top tube and I run a 55mm. or about 2.2 inch stem with a slight rise..I have a riser bar as well. The bike is very comfortable for me but if I leave it in 6inch travel on the Marzocchi 150 fork, the front is hard to keep on the ground. I have my seat well forward...about an inch from neutral. So, the distance from the top tube to the centre of the stem is about 26.8inchs. In reality it is a bit less as I have the seat so far forward. Effectively, it is about 26 inches.

    The size large Ibis has a 23.6 inch top tube and if I had a 70mm or 2.75 inch stem, it would total 26.35...If I kept the seat in a more neutral position, it would be very close to the position I have now. Does this make sense to you? If that works the next question is whether to go with the standard Fox fork or a talas 36. The longer travel fork would give me a bit slacker head angle for those steeper parts of our riding. However these are only a small part of things, and maybe as Tom at Ibis says, the 140mm. may well be just fine. Bob

  9. #9
    www.derbyrims.com
    Reputation: derby's Avatar
    Join Date
    Jan 2004
    Posts
    6,788
    Quote Originally Posted by bobAustin
    Thanks Derby....You seem up on angles, geometry etc.

    My 03 Gemini has a 24.6" horizontal top tube and I run a 55mm. or about 2.2 inch stem with a slight rise..I have a riser bar as well. The bike is very comfortable for me but if I leave it in 6inch travel on the Marzocchi 150 fork, the front is hard to keep on the ground. I have my seat well forward...about an inch from neutral. So, the distance from the top tube to the centre of the stem is about 26.8inchs. In reality it is a bit less as I have the seat so far forward. Effectively, it is about 26 inches.

    The size large Ibis has a 23.6 inch top tube and if I had a 70mm or 2.75 inch stem, it would total 26.35...If I kept the seat in a more neutral position, it would be very close to the position I have now. Does this make sense to you? If that works the next question is whether to go with the standard Fox fork or a talas 36. The longer travel fork would give me a bit slacker head angle for those steeper parts of our riding. However these are only a small part of things, and maybe as Tom at Ibis says, the 140mm. may well be just fine. Bob
    Sounds like you understand the bar reach and pedaling center fit equation. The 23.6 TT large size Mojo with your stem and centered seat should fit with very near the same reach and weight over the pedals as your pushed forward seat on the longer Gemini.

    If you have a 140mm travel fork on the Mojo you would be less behind the front wheel by almost an inch going from a 67 with your 150mm fork to 69 degree head angle with 140mm travel. A 160mm adjustable travel fork and a remote dropper type seat post would probably give you the ability to get you weight lower behind the front wheel for confidence down those super steep drops the Gemini likes so well.

    I may get a 130 - 160mm adjustable travel Rockshox Lyrik U-Turn (I run coil springs) someday to run most of the time at 140mm travel, but sometimes at 160mm to slack the steering, stretch the wheel for very steep downhill or bigger rock trail pedaling clearance. For 95% or more of my riding the 140mm travel Fox 32 fork is fine. So itís hard to justify the $900 fork and added weight.

    Your more extreme North Shore downhills may warrant the bigger taller fork use every ride, and an adjustable fork to lower for easier climbing.

    The Mojo is easy to keep the front end down when climbing with a 140mm travel fork until itís extremely steep and loose.

    Another thing to consider is getting a Gravity Dropper seat post with handlebar remote to drop the seat an inch for technical pedaling or drop to 3 or 4 inches lower for steep downhill. You might comfortably use the lighter 140mm Fox 32 fork full time if using the GD type seat post. I just bough a similar post called AMP by allmountainpost.com which has even better reviews than the great reviews for the GD post. The AMP strength and machine work looks better than the GD too.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •