Author Topic: TABR- Specialized Diverge E5 (Modify w Shimano GRX600) or buy Surly Disc Trucker  (Read 3007 times)

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Offline hoverbird

Am new to touring but planning on TABR 2021. Have entry-level Specialized Diverge E5 gravel bike, equipped with front and rear racks, Brooks B17 saddle, and three water bottle cages. Am afraid my gearing won't be low enough for the tour. Considering modifying E5 with Shimano GRX600, or buying Disc Trucker, if I can get one. Local bike shop is checking on availability. Thoughts? Suggestions?

Offline aggie

I have the GRX800 on my bike.  The front crankset is the RX810-2 and has a 31 tooth low gear.  The rear derailleur is the RX810.  My bike shop was able to fit an 11x40 cassette with no issues.   My lowest gear is 21.25 gear inches.  Not as low as I would like but good enough to tour with my gear.

Offline Pat Lamb

I'm kind of torn on what to recommend here.  I don't like saying, "Go buy a different bike" all the time, though I share your concern about the gearing.  If you've currently got a 30 tooth small ring and a 34 tooth cassette, I think you're looking at a 25 gear inch low.  If you can find a (much) bigger 8 speed cassette, and appropriate derailer and/or adapter, you might get two lower gears (down around 21 gear inches, similar to the Disc Trucker), which will really help with the steep stuff.

OTOH, there's a good chance you'll still find hills that are so long, and steep, and you've been riding so long that you're tired, so you get off and walk anyway.  There's just two gears' fewer hills to walk with the stock bike.

The other thing I'd be concerned about is hauling luggage.  Are you going to be using full on bikepacking gear, or a more traditional rack and panniers setup?  How will the bikepacking bags affect the bottle cages, if you go that way?  If you go for rack and panniers, can you attach them to the Diverge?  It looks like the Diverge's carbon fork is drilled for fork leg bags, but those will be smaller than full-on front panniers.  And while you can attach a rear rack to the dropout (I think, based on peering at the "enlarged" picture on the web site), those slightly goofy chainstays may make a P-clamp attachment to the rack top ... interesting.

So just maybe getting a Disk Trucker would be the better way to go.  Order now and hope for March delivery.  And ride the heck out of the Specialized until it gets there.  More saddle time in training is always a better thing.

Offline hoverbird

I am deeply grateful for this forum, and for your replies!

Thank you, Aggie, for getting me researching and considering gear inches. I wish I considered this when purchasing the Diverge last year, but I guess now I have something to compare to. And I know the Diverge has it's place and purpose.

Again, I am new at the game, so here is my calculation. The Diverge has a 46/34 chain ring and a 11/34 cassette, and I am running Schwalbe Marathons that are 700 x 35c. The gear inches formula I am using is: Tire Diameter x (# of Chain ring Teeth / # of Cassette Teeth). So, 27.2 x (34/34)=27.2 lowest (or Granny) gear inches. If this is true, no wonder I struggle more than I expected. Please confirm I am doing this properly.

I am roughly calculating the Disc Trucker granny gear as 26 x (26/11) is about 19.9 gear inches, which is quite enticing if true.

Thanks also, Pat! My local shop did a great job installing front and rear racks. The front Blackburn rack was tricky, and both required some modifications. I can attach photos if you are interested. I have front and rear Ortlieb panniers, and three bottle cages. I was all set to do my first multiple-day trip when the California fires hit, so that got nixed. I am planning on "touring" the TABR; not racing, so perhaps the Surly might be the way to go, and to keep the Diverge for jetting around town. My local shop is checking on lead time.

Offline John Nelson

Yes, your calculation is correct.

Is 27 gear-inches low enough? Depends. Are you young and fit or old and fat? Do you travel light or heavy? Do you object to walking? Do you plan high-mileage days or low-mileage days? Are you a spinner or a masher?

Does TABR = TransAmerica Bike Ride? Do you plan to follow the Adventure Cycling TransAmerica Trail route?

The TransAmerica Trail is pretty hilly. If instead you want to ride on interstates and federal highways (not recommended by me), they are considerably less steep.

Offline hoverbird

Thanks, John.

TABR stands for the "Trans Am Bike Race", and yes, I plan on following ACA routes. I am on the older side (57) and fairly fit, and not fat, but do have some asthma issues. I have never done anything like this other than some local overnights, but am planning on touring; not racing, averaging 60-75 miles per day. Don't really want to walk much; just spinning and pacing along. I plan on using four panniers and camping gear, with motels or similar every 3rd or 4th night. I realize I will be in the back of the pack, and that is okay with me!

27 gear inches is not low enough in my past year training experience, which is why I am considering the Surly or GRX drive train overhaul. Thanks to this forum, I am enlightened as to the importance of considering gear inches.

Offline jwrushman

I did the Northern Tier last year with a fully-loaded (four paniers, camping gear, etc) Disc Trucker and didn't have to get off to walk.  My impression is that the hardest part of the Trans-America is not the Rockies, but the hills east of the Mississippi with steep uphills, steep downhills and repeat. 

I live in NJ and there are no roads here where I could simulate the climbs I experienced in the west.  In the west, the hills may not be particularly steep, but they were 15+ miles long.  I tried to plan my rides so I'd have the worst climbs early in the morning.  I couldn't do that in the Midwest and NJ - it's always up and down, up and down, up and down.  No rest until you stop.  But when I got to the Rockies, I knew I was physically and mentally ready. 

I did my ride with a Disc Trucker.  Although it's not a FUN! bicycle to ride, it was very reliable.  Whatever I was up for doing, it could handle.  The autumn before my trip, I took my Surly up to Smugglers Notch in Vermont.  I think that may be the steepest, sustained hill I've done.  I had tried it before with rental bikes, but that was the first time I had made it to the top without stopping.  A great experience letting me know we could make it out west. 

If you are new to touring, my most important advice is to load up your bike - with whatever you think you'll bring - and start doing overnighters.  You'll learn what gear you need, what you don't, and give you confidence in your set-up.

John R.
Planning for 2022!

Offline AngrybirdP

I would love to see that front rack install. I've reached out to Speacialized about those lower OTB holes that are drilled smaller than stand rack/water bottle mounts and seem reluctant to give me a real answer about what they are for. Instead try to convince me that their "Pug n' Play system is to be used for racks. Are you familiar? It's absurd really.

Offline jwrushman

"...I would love to see that front rack install..."

To whom are you replying?  Hoverbird?

John R

Offline Pat Lamb

My local shop did a great job installing front and rear racks. The front Blackburn rack was tricky, and both required some modifications. I can attach photos if you are interested. I have front and rear Ortlieb panniers, and three bottle cages. I was all set to do my first multiple-day trip when the California fires hit, so that got nixed. I am planning on "touring" the TABR; not racing, so perhaps the Surly might be the way to go, and to keep the Diverge for jetting around town. My local shop is checking on lead time.

After reflection, I'm thinking about revising my previous recommendation.  Since you're working with a good shop, you've got a few more options open to you.  And I'm cheap, so if you can make what you've got work, that's probably cheaper than buying another bike. 

So I'd first take your bike down and ask if they can put a smaller chainring on, and the larger cassette aggie mentioned.  Question: did that require a Wolftooth derailer hanger droppers?  (Not sure about the right name.)  If they can put on a 30 tooth ring and get the rear working with a 40 tooth cog, you're at about 21 gear inches.  Since you've got the racks sorted out, the Diverge would then be ready to ride.
Save the extra money for luxuries like a motel room when you're knackered or a steak dinner when you're famished. 

Offline aggie

My 11-40 cassette did not require the derailer hanger change.  There is a video on youtube by bikepacking.com that talks about this setup and changing the derailer hanger.

Offline HikeBikeCook

  • World Traveler
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  • Touring for over 50 years and still learning
One thing to consider is frame geometry and rider position. We just bought a pair of Disc Truckers (last year) for a cross country trip in 2022 or 2023. I have toured with a little bit of everything from Peugeot, to Raleigh, to Litsepseed, and a Scott Scale mountain bike (GAP & C&O) I have sore solders and numb hands after hours in the saddle and cross country riding in my mind is about comfort over long distance versus speed.

#1 - Can you load up your current bike and ride 50 to 75 miles a day for 2 or three months and be comfortable?

#2 - Can you afford to drop $1,500 on a Disc Trucker - plus $$ to outfit and not lay awake thinking about it?

#3 How many bikes does a bike enthusiast need? N+1 - N=current number owned :)

Sometimes joy is in finding the right tool for the job.
Surly Disc Trucker, Lightspeed Classic, Scott Scale, Klein Mantra Comp. First touring bike Peugeot U08 - 1966

Offline DaveB

After reflection, I'm thinking about revising my previous recommendation.  Since you're working with a good shop, you've got a few more options open to you.  And I'm cheap, so if you can make what you've got work, that's probably cheaper than buying another bike. 

So I'd first take your bike down and ask if they can put a smaller chainring on, and the larger cassette aggie mentioned.  Question: did that require a Wolftooth derailer hanger droppers?  (Not sure about the right name.)  If they can put on a 30 tooth ring and get the rear working with a 40 tooth cog, you're at about 21 gear inches.  Since you've got the racks sorted out, the Diverge would then be ready to ride.
Modifying the Diverge to get significantly lower gearing is going to be more involved and expensive than it appears.

First, the OEM Claris crank has a 110 mm BCD so 34T is the smallest practical chainring (yeah, 33T will fit but good luck finding one).  There is a Claris triple crank (50/39/30) but that will require buying a new crank and Octalink triple bottom bracket.

Second 8-speed cassettes are way out of date and the selection is limited. Finding one with a larger largest cog than 34T is probably unobtanium.  Those huge cog cassettes intended for 1X drivetrains start a 9-speed and are far more common at 10 and 11-speed.

Modifying the Diverge with GPX600 (11-speed) will fix the gearing problems but at a much greater cost as he will have to change the shifters, both derailleurs, crank, bottom bracket, cassette, brakes and rear wheel.

By the time the OP has modified his Diverge he is well on his way to paying for a Disc Trucker that comes far better geared and with better components (groupset, brakes and thru axle wheels) than his Diverge.  I think it's time for N+1