My Calculus Munga Bike Built

[Pure Savage]

Mullet Gravel Bike 

Business at the front party at the back??

[TyronLab]

That's rather awesome even just from a uniqueness perspective. Also, as an engineer, Titanium anything is automatically just better.

 

One question I have though, none of your "suspension" on this build is dampened, so there's no resistance to the spring effect you get from the tyre / fork leaves compressing. Although your unsprung mass is OK, depending on the frequency of the bumps and the frequency of your "spring", it may end up being quite bouncy. Have you found this to be the case at all vs dampened suspension (standard fork and rear shock)?

 

Please don't take this as a critique, just interested in the mechanics of it all vs actual feel on the bike. I'm strongly contemplating going for a plus hardtail for my next bike as opposed to a full susser for the Gauteng marathons I inevitably end up doing. The bouncyness of a plus bike is something that might put me off of that, so looking to get your real-world inputs.

[George Mungrel]

Thanks for all the great comments. Just to answer a few questions so far:

I'm using a SON Dynohub charging my power bank during the day and for the light at night.

Yes I agree, the small FARR aero bar will be great and is on order.

The drop bar is a SALSA Cowchipper carbon 44cm.

Cassette is a 9x45 and the chainring will be a 36, still running a 34 at the moment.

Back tire is the Schwalbe G-One all round 27.5" 2.8

Regarding damping...Yes the Lauf has no damping and progressive spring rate. I do not find the Lauf bouncy at all when sitting but yes it do have a bit of a bounce when standing.

Tire pressure on a plus size tire is important, it will for sure bounce if the pressure is really low and the cadence high. There will always be a compromise between speed and comfort.

If the spring rate matches the corrugation frequency its a extremely smooth ride but can be hard on big wide corrugations.

[George Mungrel]

Nice. Does no one use a dyno hub? No need for extra batteries. Seems weird to me. Good luck on your race.

Thank you. Yes the SON Dynohub will be used for sure

[George Mungrel]

I love it, such a cool build! You can see this has been very well thought out and is fit for purpose!

 

Is there enough clearance in the back triangle to take a 29x2.2 - 2.4" tyre should you want to use the bike for something like a 36One that is a bit shorter where you may not need as much comfort in the back as a Munga?

 

Another question - what tyre is that on the back?

 

Oh, maybe something to consider to keep the look nice and slick. Farr make an aero top tube bag, that attaches to the frame with two bolts. This being a custom build I am sure Calculas can add two bosses to the top tube. It will make the bike look really clean by doing away with the straps of the bag you have now...

 

EDIT: the top tube bag I am talking about: https://ridefarr.com/product/aero-toptube-bag/

 

May also be worth it to consider adding their areo bolt on for more hand positions: https://ridefarr.com/product/handlebar-carbon-farr-aero-bolt-on/

 

PS, I have no affiliation with Farr.

 

Yes I do have a 29" back wheel option for shorter faster rides like the 360. Frame will also be able to accommodate up to a 2.6 29" at the back.

[George Mungrel]

Is that it on the bike? That looks like a normal DT Swiss hub to me.

In the last photo I have the SON hub wheel. For normal training and riding I use the DT Swiss.

[Long Wheel Base]

My word that is a nice build. Keen to watch your dot and hopefully get a post race report from you?(I know in race reports is too much too ask).

[George Mungrel]

In the last photo I have the SON hub wheel. For normal training and riding I use the DT Swiss.

A few more photos

[WGoosen]

I hardly use the drops on my road bike so I figured I would be wasting my time. Due to a weak core I find it puts too much pressure on my hands. My conundrum right now is hoping I can get my extended battery from Garmin in time and figuring out how to carry all my hydration

Hydration I find is the biggest issue for me. I did two 250km + solo rides through the Ceder Mountains and Tankwa, both times dehydration caused me to abandon the planned 350km ride. First ride I took 2 bottles and a camelback, second time I had 5.70liters of water, 2 special large 950ml and 1 750ml and a 3l bladder in a frame bag. This should be enough taking in account distance between water points even if I loose bottles or experience excessive heat - I just don't want to ever run out of water is what I learned on the two rides.

[Monark]

Epic. I love ti builds.

[Ramrod]

Hydration I find is the biggest issue for me. I did two 250km + solo rides through the Ceder Mountains and Tankwa, both times dehydration caused me to abandon the planned 350km ride. First ride I took 2 bottles and a camelback, second time I had 5.70liters of water, 2 special large 950ml and 1 750ml and a 3l bladder in a frame bag. This should be enough taking in account distance between water points even if I loose bottles or experience excessive heat - I just don't want to ever run out of water is what I learned on the two rides.

Yeah I am not one for a camel back. I find they hurt my shoulders too much. Thus the conundrum. I can fit two bottle on my frame and a third on my saddle bag but I think the sun will make that one undrinkable due to the heat. I can do the side by side bottle option but don't want to loose the swat box which will be carrying essential spares.

[WGoosen]

Yeah I am not one for a camel back. I find they hurt my shoulders too much. Thus the conundrum. I can fit two bottle on my frame and a third on my saddle bag but I think the sun will make that one undrinkable due to the heat. I can do the side by side bottle option but don't want to loose the swat box which will be carrying essential spares.

Yes camel back killed me ride one thats why I moved the bladder to a frame bag in frame. See the two one litter bottles here attached with wolf tooth system. Tested it on serious corrugation in Tankwa - just add cable-ties.

[WGoosen]

I have a rear bike rack which I use for touring. It is extremely light. I would probably use it for this race if I did it. I would not like so much weight on the front. I wish you both good luck. I will do this race one day.

sure agreed, the front bag in this case was just because I did a solo unsupported ride and had to take extra clothes.

[Shebeen]

I have a rear bike rack which I use for touring. It is extremely light. I would probably use it for this race if I did it. I would not like so much weight on the front. I wish you both good luck. I will do this race one day.

Thule one?

 

Traditional hard tail Rear bike racks do not like corrugations if loaded up.

[George Mungrel]

Yes camel back killed me ride one thats why I moved the bladder to a frame bag in frame. See the two one litter bottles here attached with wolf tooth system. Tested it on serious corrugation in Tankwa - just add cable-ties.

Yes camel back killed me ride one thats why I moved the bladder to a frame bag in frame. See the two one litter bottles here attached with wolf tooth system. Tested it on serious corrugation in Tankwa - just add cable-ties.

This is also a great option for an extra water bottle.

 

https://www.evobikes.co.za/wolftooth/wolftooth-b-rad-double-bottle-adapter.html

[WGoosen]

This is also a great option for an extra water bottle.https://www.evobikes.co.za/wolftooth/wolftooth-b-rad-double-bottle-adapter.html

yes this is the system I used - but take note - add cable-ties - the screws vibrated out on both long rides