Learning how to pick your Steadfast Golf shaft starts with flex, and this guide builds that choice around the ball speed ranges on the JUPITER One page. It also covers the Jupiter Lite driver shaft and a three shaft bundle, with prices and order options drawn from Steadfast’s own product pages.
Key Takeaways
- Senior covers 70 to 89 mph ball speed, while X Stiff covers 110 to 129 mph.
- Jupiter Lite lists no ball speed ranges, leaving flex choice with less to go on.
- The 60 day flex exchange is listed, though exchange shipping cost and fees stay unclear.
- Adapter and grip are installed before shipping, so match the adapter to your head.
Why Flex Is the Main Choice on a Steadfast Golf Shaft
Steadfast Golf sells aftermarket golf shafts in two lines, Jupiter One and Jupiter Lite, and both come in four flexes: Senior, Regular, Stiff and X Stiff. The adapter and grip are already installed, according to Steadfast, so by the time an order ships the main decision a buyer has made is the flex.
On the Jupiter One page, each flex has its own weight, CPM number and ball speed range. The sections below use that table to show how the four flexes differ, and how to choose between them.
The Jupiter One Flex Table
The Jupiter One Driver Shaft page lists four flexes, each with a weight, a CPM number and a ball speed range. Every flex has the same 45.5 in play length. The figures below come straight from the page.
- Senior: 50g, 227 CPM, ball speed 70 to 89 mph.
- Regular: 55g, 241 CPM, ball speed 90 to 99 mph.
- Stiff: 58g, 258 CPM, ball speed 100 to 109 mph.
- X Stiff: 61g, 273 CPM, ball speed 110 to 129 mph.
Weight and CPM both rise from Senior to X Stiff. The page labels the ranges as ball speed, not clubhead or swing speed, so this guide does not convert between them. The page does not give a torque or tip size figure as a number, only a “special low torque design” description.
How to Use the Ball Speed Ranges
The four ranges on the Jupiter One page sit back to back: 70 to 89 mph, 90 to 99, 100 to 109 and 110 to 129. They meet at 89 and 90, at 99 and 100, and at 109 and 110. If you know your ball speed, the table gives a starting point, and the steps below help when your number sits near an edge.
- Match your number to a range: Find where your own ball speed falls, then read the flex, weight and CPM beside it.
- Near a boundary, keep the exchange in mind: Steadfast’s refund policy gives you 60 days to try a shaft and swap it for a different flex. Custom shafts are not eligible, and exchange shipping is your cost unless you add Checkout+.
- Compare the weight in grams: The flexes run from 50g for Senior to 61g for X Stiff, so a step up the table is also a step up in weight.
The page does not say any flex will suit every golfer in its range, so use the table as a guide and not as a rule.
Choosing Within Jupiter Lite
Jupiter Lite offers the same four flex names as Jupiter One: Senior, Regular, Stiff and X Stiff. The Driver Shaft is listed at $199.95, with $249.00 shown as the regular price. The page lists the shaft at 45 to 46g and describes it as “10 grams lighter than previous models,” with a softened tip section. It was developed with shaft designer Steve Sacks.
The Lite page does not give ball speed ranges, so they are Information could not be verified, and its CPM values are also Information could not be verified because the page shows two sets that disagree. For that reason, this guide does not apply the Jupiter One ranges to Jupiter Lite, and the table in the previous section covers Jupiter One only.
If the Flex Isn’t Right: The 60 Day Exchange
Steadfast Golf’s refund policy gives you 60 days to try a shaft and exchange it for a different flex. The product pages say the 60 days run from receipt. The policy covers exchanges, and it does not mention refunds.
- Exchange window: You have 60 days to play the shaft and swap it for a different flex through Steadfast’s returns portal.
- Custom shafts: Custom builds are not eligible for exchanges.
- Shipping cost: Without the optional Checkout+ add on, you pay the exchange shipping. Checkout+ costs a small fee at checkout, and the policy does not state the amount.
- Breakage replacement: Steadfast says it will replace a shaft that breaks, but the lifetime replacement is voided by any pull out or reinstallation.
Setting Up Your Order: Adapter, Hand and Grip
Once the flex is chosen, the order options are what decide whether the shaft fits your club. Steadfast installs the adapter and grip before shipping, so pick each option carefully on the product page.
- Adapter: The list includes Callaway, Cleveland, Cobra, Mizuno, Ping, PXG, Srixon, TaylorMade, Titleist, Tour Edge, Vice Golf and Wilson, plus a Raw option. Some brands have more than one listing, such as Ping 400, Ping 410/425/430 and Ping 440, or Srixon Flat, Srixon Upright and Srixon ZXi, so match yours to your head.
- Hand and grip: Choose Right or Left hand, and a Standard or Midsize grip.
- Custom Build: Custom Build versions of the woods and the Jupiter Lite driver list at the same price as the standard shafts, but custom shafts are not eligible for the flex exchange.
Three Ways to Buy Steadfast Shafts
Steadfast Golf sells its shafts as single driver shafts and as bundles, and three options fit the flex advice above. The JUPITER One Driver Shaft is $149.95 and has the published ball speed table. The Jupiter Lite Driver Shaft is $199.95 and is the lighter option. The JUPITER One Driver + 3 + 5 Wood Shaft Bundle is $359.95 and covers three clubs in one order. Check each product page for current prices, flexes and adapter options before you order.
 JUPITER One Driver Shaft
The JUPITER One is Steadfast Golf’s main driver shaft. It comes in four flexes, and each flex is matched to a ball speed range, so golfers can choose by their own numbers. It suits anyone who knows their driver ball speed and wants to fit a shaft to their current driver head.
- Four flexes tied to ball speed: Senior (50g, 227 CPM, 70 to 89 mph), Regular (55g, 241 CPM, 90 to 99 mph), Stiff (58g, 258 CPM, 100 to 109 mph) and X Stiff (61g, 273 CPM, 110 to 129 mph).
- 21 adapter options listed, including Callaway, Cobra, Ping, PXG, TaylorMade, Titleist and Srixon.
- Adapter and grip come already installed by Steadfast’s club fitters.
- Right hand or left hand, with a Standard or Midsize grip.
- 45.5 inch play length.
Price: $149.95 per shaft on the product page. A 60 day flex exchange is listed if the flex does not suit you, and the exchange shipping cost and any fee are not clearly stated, so check the exchange page before you order.
Jupiter Lite Driver Shaft
The Jupiter Lite is Steadfast Golf’s lighter driver shaft, developed with shaft designer Steve Sacks. It suits golfers who want a lighter shaft with a softer tip section and are fine choosing a flex without a published ball speed range. Steadfast does not list ball speed ranges for this shaft, so the Jupiter One flex table in this guide is the better starting point if you want to match flex to your numbers.
- Four flexes: Senior (A), Regular (R), Stiff (S) and Extra Stiff (X).
- Listed weight of 45 to 46g for Regular, Stiff and Extra Stiff, and Steadfast says it is 10 grams lighter than its previous models.
- Softened tip section, which Steadfast says improves launch angle and responsiveness.
- Same 21 adapter options as the Jupiter One, with right or left hand and a Standard or Midsize grip.
- Spec table lists CPM of 245 for Stiff and 255 for Extra Stiff, with Regular marked “coming soon” and Senior not shown in the table.
Price: $199.95, marked down from the $249.00 regular price shown on the product page. The same 60 day flex exchange applies, so check the exchange page for shipping cost and fees before you order.
JUPITER One Driver Wood Shaft Bundle
This bundle puts a JUPITER One driver shaft, 3 wood shaft and 5 wood shaft in one order. It suits golfers who want to re shaft their driver and two fairway woods at the same time. Steadfast says the bundle is priced below buying each shaft on its own.
- Contains one JUPITER One Driver Shaft, one JUPITER One 3 Wood Shaft and one JUPITER One 5 Wood Shaft.
- Four flex options: Senior, Regular, Stiff and X Stiff. The product page does not list ball speed ranges or weights for the fairway wood shafts.
- 20 adapter options listed, including Callaway Quantum, Cobra, Ping, PXG, TaylorMade and Titleist. Vice Golf and Wilson, which appear on the single driver shaft page, are not listed here.
- Right hand or left hand, with a Standard or Midsize grip.
- Same 60 day flex exchange wording as the other Steadfast shafts.
Price: $359.95 for all three shafts. Compare this with the $149.95 JUPITER One driver shaft on its own, and check the exchange page for shipping cost and fees before you order.
Price and Shipping Context
The JUPITER One Driver Shaft is priced at $149.95, and the bundles start at $239.95. A banner on the Steadfast site offers free shipping on orders over $175, so a single JUPITER One shaft on its own sits below that line while a bundle sits above it. Shipping rates, regions and delivery times: Information could not be verified, so check the shipping details at checkout before you order.
Summary
This guide covered how to pick a Steadfast Golf flex using ball speed. The JUPITER One Driver Shaft comes in four flexes: Senior for 70 to 89 mph, Regular for 90 to 99 mph, Stiff for 100 to 109 mph and X Stiff for 110 to 129 mph. It also looked at the Jupiter Lite Driver Shaft at $199.95 and the JUPITER One Driver + 3 + 5 Wood Shaft Bundle at $359.95.
The standout feature is the ball speed table on the JUPITER One at $149.95, which lets a golfer choose a flex from a number instead of a guess. Each shaft arrives with the adapter and grip already installed, and there are 21 adapter options, right or left hand, and Standard or Midsize grip. The Jupiter Lite is listed at 45 to 46g, but Steadfast does not publish ball speed ranges for it, so its flex choice has less to go on.
Two steps make the order safer. First, find your driver ball speed and match it to the range, then confirm the adapter fits your driver head before checkout. Second, read the exchange page before ordering, because the 60 day flex exchange is listed but the exchange shipping cost and any fee are not clearly stated, and a single JUPITER One shaft at $149.95 falls below the $175 free shipping banner.
